32 Vitamin D Benefits And Side Effects

There are so many people who take Vitamin D every day but do you know what is Vitamin D benefits and side effects?

Vitamin D is a basic nutrient for maintaining health. It is also a member of the steroid hormone family. It was discovered in the early 20th century to prevent rickets in children. The fourth in the vitamin sequence.

Globally, its lack is a major public health problem affecting all ages and ethnic groups and has surpassed iron deficiency as the most common nutritional deficiency in the world.

The two main subtypes are Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol), which have similar effects, and these subtypes will not be distinguished in the text unless otherwise stated.

What is the effect of Vitamin D supplementation? Are there any side effects or contraindications? See the text analysis for details.

Table of Contents

What is Vitamin D?

Vitamin D is a micronutrient that can be metabolized into a multi-functional steroid hormone vital to human health. In addition to being an important part of maintaining calcium balance and bone health, it is also combined with Vitamin D receptors throughout the body ( Such as the brain, blood vessels, prostate, breast, and immune cells), directly or indirectly affect more than 2,000 groups of genes, but also have non-genomic rapid effects, including direct stabilization of the endothelium.

The proven physiological activities of Vitamin D also include: inhibiting cell proliferation and inducing differentiation, inhibiting angiogenesis, stimulating insulin secretion, inducing apoptosis, inhibiting the production of renin, and stimulating the production of macrophages.

Current studies have also found that Vitamin D deficiency is closely related to the occurrence and development of many chronic diseases, including metabolic abnormalities, osteomalacia, osteoporosis, muscle weakness, hip fracture, diabetes, cancer, cardiovascular disease, arthritis, autoimmune diseases.

At present, there is no one nutrient, medicine, the hormone that can get so many scientific verifications that are beneficial to the human body like Vitamin D.

What are the symptoms of Vitamin D deficiency?

Listed below are the possible non-specific clinical symptoms:

  • Frequent illness or infection
  • Easily tired
  • Pain in joints, bones or muscles
  • Depression and depression
  • The wound is difficult to heal
  • Reduced bone density or frequent fractures
  • Thinning hair or easy to fall off

What groups are prone to lack of vitamin D?

Seniors: As you age, your skin will become thinner, which makes it more difficult for your skin to produce Vitamin D3 in the sun.

However, some young people have difficulty moving due to joint deterioration, often leaving home. This means less exposure to sunlight, and the sunlight is the best way to naturally increase Vitamin D levels.

Darker complexion: This means more melanin in the skin, the higher the concentration, the better the skin is protected from the sun’s ultraviolet rays.

However, it also reduces the body’s ability to produce Vitamin D3 from the skin, which may make you prone to a lack of Vitamin D3.

Living far away from the equator: near the equator is sunny all year round. In contrast, countries farther from the equator have less sunshine throughout the year (especially in winter, where there is less sunshine).

Suffering from diseases related to poor fat absorption: Vitamin D is fat-soluble, so the degree of absorption also depends on the ability of the intestine to absorb fat from the diet.

Therefore, groups with diseases related to poor fat absorption are prone to lack of Vitamin D, including irritable bowel disease, Crohn’s disease, liver disease, and patients who have undergone bariatric surgery.

What are the benefits recommended for Vitamin D?

1. Vitamin D benefits autism

Autism Spectrum Disorder is a group of neurodevelopmental disorders. Patients may have the following characteristics: difficulties in expressing and understanding certain emotions, difficulties in understanding others’ emotions, expressive language disorders, abnormal eye contact, and like to try their best Few changes, restricted use of toys, and prefer to play in isolation (approximately 90 to 250 out of 10,000 people are sick).

According to the main symptoms of children, autism spectrum disorders are composed of different subgroups, including autistic disorder, Asperger Syndrome, and Pervasive Developmental Disorder.

A meta-analysis of literature (including 3 randomized controlled trials, a total of 203 children with autism spectrum disorder) pointed out that Vitamin D supplementation can improve the typical symptoms of autism spectrum disorder (in terms of social response capacity Table and Child Autism Rating Scale scores).

*Conclusion: Vitamin D supplementation may have a positive effect on improving childhood autism, but it is limited by the small sample size, and more large trials are needed.

2. Vitamin D benefits chronic obstructive pulmonary disease

Chronic Obstructive Pulmonary Disease is a respiratory obstructive disease, clinical manifestations include dyspnea, chronic cough, low exercise capacity, tinnitus, bronchial infection, another manifestation of late weight loss.

Smoking is the main risk factor for chronic obstructive pulmonary disease. Among people aged 30 to 60 years old with normal lung function and continuous smoking, at least 20.7% develop moderate chronic obstructive pulmonary disease, and this proportion of non-smokers 3.6%.

Risk factors for non-smokers with chronic obstructive pulmonary disease include asthma, advanced age, low education, occupational toxin exposure, and childhood airway infection history.

A meta-analysis of literature (including 25 randomized controlled trials, a total of 2,670 patients with chronic obstructive pulmonary disease) pointed out that Vitamin D treatment can improve lung function evaluation indicators.

*Conclusion: Vitamin D supplementation can bring positive help to chronic obstructive pulmonary disease, but more research is still needed to further verify.

3. Vitamin D is beneficial to cancer events

Cancer is the leading cause of death in the world’s population, second only to heart disease. Related cancer risk factors such as smoking, drinking, ultraviolet radiation, human papillomavirus infection, chronic diseases such as obesity, and type 2 diabetes.

It is estimated that one out of every two people develops cancer during their lifetime. This number was one third at the turn of the century. Fortunately, some types of cancer, especially colorectal cancer, breast cancer, and prostate cancer can be found through routine screening to detect malignant lesions early.

A pooled analysis (Pooled Analysis, including 2 cohort studies on 2,304 women over 55 years old) pointed out that compared with subjects whose blood 25(OH)D concentration is less than 20 ng/ml (which is Vitamin D deficiency) If 25(OH)D is greater than 40 ng/ml, it can reduce the risk of cancer by 67%.

Another literature analysis (meta-analyses, including 64 observational studies, a total of 44165 cancer cases) pointed out that a higher blood Vitamin D value (25OHD) is associated with lower cancer mortality and the rate of disease progression, while Vitamins D receptor gene mutations also worsen the prognosis of cancer events.

A meta-analysis of literature (including 10 randomized controlled trials, a total of 81362 participants) pointed out that Vitamin D supplementation can reduce cancer mortality (but not helpful for cancer incidence), and the related effect is most significant in the following subjects, Such as no history of cancer, take Vitamin D or calcium supplements.

*Conclusion: Vitamin D deficiency is associated with a higher cancer incidence and poor prognosis, and supplementation or permission to reduce cancer-related mortality.

4. Vitamin D is good for tuberculosis

Over the past 200 years, an estimated 1 billion people have died of tuberculosis, which infects one-third of humans and is the leading cause of infectious death worldwide, comparable to the impact of HIV.

Sputum smear-positive pulmonary tuberculosis patients are the main source of tuberculosis infection because when they cough or sneeze, they will discharge small droplets carrying infectious bacilli. An untreated infectious tuberculosis patient can infect 10 to 15 people each year.

A meta-analysis of literature (including 5 randomized controlled trials, a total of 1126 tuberculosis participants) pointed out that Vitamin D supplementation did not shorten the time of sputum culture and smear conversion, nor did it increase the proportion of negative sputum culture.

However, in the subgroup of participants with the TaqI tt genotype, it shortened the time for sputum culture conversion and increased the conversion rate of sputum culture for MDR-TB.

*Conclusion: Overall, Vitamin D supplementation has no obvious benefits against anti-TB treatment.

5. Vitamin D is beneficial for Helicobacter pylori infection

Helicobacter pylori is a Gram-negative, microaerobic, spiral-shaped bacteria, mainly distributed in the human stomach, is one of the most common infections in the world, the gastric mucosa of more than 50% of the global population Helicobacter pylori exists in all.

Colonization of Helicobacter pylori can cause chronic gastritis in all infected people. Most infections are asymptomatic, however long-term infection increases the risk of site-specific disease. 10% to 15% of infections can cause peptic ulcers, 95% of duodenal ulcers and 80% of gastric ulcers are related to helicobacter pylori.

A meta-analysis of literature (including 10 studies) pointed out that patients with positive Helicobacter pylori had low Vitamin D levels.

In addition, patients who successfully eradicate H. pylori have higher levels of Vitamin D, while patients who lack Vitamin D have a higher failure rate to eradicate H.

*Conclusion: Vitamin D may be an important protective factor for Helicobacter pylori infection, but the relevant results still need more research to further verify.

6. Vitamin D is beneficial to gestational diabetes

Gestational diabetes mellitus is defined as the first finding of any degree of glucose intolerance during pregnancy. It is a disease-specific to pregnancy. It is estimated that 1 in 7 live births worldwide is affected by the disease.

Risk factors related to the onset are increased age of pregnant women, obesity, ethnic background, history of huge fetuses, past adverse pregnancy outcomes, family history of polyhydramnios type 2 diabetes, and history of gestational diabetes.

A systematic literature review and meta-analysis (including 6 randomized controlled trials involving a total of 454 pregnant women diagnosed with gestational diabetes during the second or third trimester) indicated that Vitamin supplementation compared to placebo or untreated subjects D can reduce neonatal complications, such as hyperbilirubinemia, polyhydramnios and the need for maternal and child hospitalization (but limited to a small number of samples, low evidence).

*Conclusion: Up to now, there is no high-quality evidence that Vitamin D supplementation in gestational diabetes can improve glucose metabolism and maternal-infant related complications.

7. Vitamin D is beneficial for blood lipid regulation

Serum lipid profile is an important indicator of cardiovascular disease risk prediction, has now become a routine detection method of cardiovascular disease.

The test includes four basic parameters: total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. Common abnormalities can be divided into elevated plasma low-density lipoprotein, elevated plasma triglyceride, and decreased plasma high-density lipoprotein.

A systematic literature review and meta-analysis (including 41 randomized controlled trials with a total of 3434 participants) pointed out that Vitamin D supplementation can help improve serum total cholesterol, low-density lipoprotein cholesterol, and triglycerides (but HDL cholesterol did not improve significantly).

In addition, the improvement in total cholesterol and triglycerides was more pronounced among participants with Vitamin D deficiency.

*Conclusion: For hyperlipidemia patients with Vitamin D deficiency, additional supplementation may be positively helpful for blood lipid regulation.

8. Vitamin D boosts male hormones (androgens)

Androgen, also known as androgen, or male sex hormone, is defined as a substance that can develop and maintain male characteristics in reproductive tissues (especially reproductive tract, the second sex, and fertility), and contribute to the synthesis of body tissue Metabolic state.

Testosterone is one of the major androgens in the circulation of mature male mammals and is associated with decreased testes, spermatogenesis, enlarged penis, and testes increased libido, hair type, sound changes, and deepened sounds.

Testosterone levels will decrease with aging, and there will be reduced testicle size, decreased libido, decreased bone density, decreased muscle quality, increased fat production, and reduced red blood cell production.

A systematic review and meta-analysis (meta-analysis, including 8 of 1061 adult male participants) pointed out that Vitamin D supplementation (daily doses range from 600 IU to 4000 IU to 60000 IU per week, expected 6 By week 144), there was no significant effect on total testosterone and sex hormone-binding globulin.

*Conclusion: Up to now, there is no evidence to support Vitamin D supplementation to enhance male hormones, but due to the limited number of studies and possible interference factors, more large-scale randomized controlled trials are still needed to corroborate.

9. Vitamin D reduces birth events at low birth weight and small gestational age

Low birth weight is defined by the World Health Organization as having a birth of less than 2.5 kg. It is estimated that 15% to 20% of newborns worldwide are born with lower body weight each year.

In addition, low birth weight and small gestational age may promote intracranial hemorrhage, respiratory distress, sepsis, blindness, gastrointestinal disease, long-term neurological dysfunction, language development disorder, impaired academic performance, cardiovascular disease, And diabetes risk.

A systematic literature review and meta-analysis (including 13 randomized controlled trials) pointed out that maternal supplementation of Vitamin D during pregnancy (supplemented alone, not combined with other micronutrients) is in addition to the birth weight, length and head circumference of the newborn It has a positive effect and can also reduce the risk of low birth weight and small for gestational age.

*Conclusion: Vitamin D is an essential nutrient for fetal growth and development, which has a positive effect on the size of the newborn. However, due to the limited number of studies, more research is still needed to further assess the influence of genetic, environmental, social demographic, and lifestyle factors.

10. Vitamin D helps lose weight

Overweight and obesity are the results of the imbalance between daily energy intake and energy consumption, which leads to excessive weight gain and is the second most preventable cause of death after smoking.

Overweight and obesity are defined according to body mass index (BMI), which is the weight (kg) divided by the square of height (m), and the healthy BMI range is 18.5 to 24.9 kg/m2. Overweight is defined as BMI between 25 and 29.9 kg/m2, and obesity is defined as BMI ≥ 30 kg/m2.

A systematic literature review and meta-analysis (including 11 randomized controlled trials, a total of 947 overweight and obese adult participants) pointed out that Vitamin D supplementation can reduce body mass index (-0.32 kg/m2) and waist circumference ( -1.42 cm), but has no significant effect on body weight indicators.

The underlying mechanism may be related to Vitamin D inhibiting parathyroid hormone, supporting intestinal calcium absorption, and stimulating insulin receptors.

*Conclusion: Vitamin D supplementation may be beneficial for weight loss, but it is limited by the heterogeneity of the included studies, and more studies are needed to confirm its clinical benefit.

11. Vitamin D prevents cardiovascular disease

Cardiovascular diseases refer to all diseases related to the heart and circulatory system.

These diseases can be caused by modifiable or unmodifiable factors, such as smoking, physical activity, dietary health, blood pressure, body weight, glucose and cholesterol levels

Unchangeable factors such as age, gender, family history, especially first-degree relatives who develop the disease before 55 years (male) or 65 years (female) (such as atherosclerotic disease) are considered to be an independent inheritance Risk factors.

A meta-analysis of literature (including 21 randomized controlled trials with a total of 83,291 participants) pointed out that compared with placebo, Vitamin D supplementation was not associated with a reduction of major adverse cardiovascular events, but also with myocardial infarction, stroke, heart The secondary indicators of vascular disease mortality or all-cause mortality were not relevant.

*Conclusion: As of now, there is no evidence that supplementing Vitamin D can reduce the incidence of cardiovascular disease.

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12. Vitamin D is beneficial for multiple sclerosis

Multiple sclerosis is a chronic inflammatory demyelinating disease of the central nervous system, commonly seen in residents of high latitudes, and the risk of females is higher than that of males (gender ratio 2.5:1)

This disease leads to secondary macrophage aggregation and subsequent myelin sheath destruction and is therefore considered an autoimmune disease. All nerve functions (motor, cerebellum, brain stem, sensation, sphincter, vision, mental state) may be damaged during the attack

A Cochrane Database Systematic Reviews (including 12 randomized controlled trials, a total of 933 multiple scleroses) pointed out that supplemental Vitamin D for the annualized relapse rate and expanded disability status scale ( Expanded Disability Status Scale) and gadolinium-enhancing T1 lesions have no obvious effect.

*Conclusion: As of now, oral Vitamin D has no obvious effect on the improvement of multiple sclerosis, but it is limited by the high bias risk of the included studies, and more studies are still needed to confirm its clinical benefit.

13. Vitamin D can improve asthma

Bronchial asthma, also known as asthma, is a chronic inflammatory disease of the respiratory tract, manifested by repeated attacks of wheezing, difficulty breathing, chest tightness, and cough, usually in the evening or early morning.

It is characterized by airway hyperresponsiveness and variable airflow obstruction, which is often reversible, either spontaneously or through treatment.

About 10% of children and 5% of adults suffer from bronchial asthma. The greatest risk factor is the ectopic constitution, for example, the genetic tendency to produce IgE antibodies against pollen, dust mites, fungi, or animal-derived proteins.

A meta-analysis of literature (including 14 randomized controlled trials, a total of 1421 asthma patients) pointed out that Vitamin D can significantly reduce the rate of asthma exacerbation (by 27%).

In the subgroup analysis, it was found that the improvement in the rate of asthma exacerbation was most pronounced in subjects with Vitamin D deficiency (Vitamin D < 30 ng/ml).

The improvement of forced expiratory volume in the first second (FEV1%) is more significant with Vitamin D deficiency and airflow limitation (air limitation is defined as FEV1% < 80%).

*Conclusion: Vitamin D may be helpful for improving asthma, especially the population with Vitamin D deficiency, but it is limited by the potential interference factors such as small sample size and clinical heterogeneity. More research is needed to prove.

14. Vitamin D is beneficial for severe depression

Major depression disorder is one of the most common mental disorders, also known as clinical depression.

In the United States, approximately 7% to 9% of adults experience a major episode of major depression each year, and an estimated 8 million people meet the criteria for major depression.

Although the physiological factors that trigger the development and progression of major depression are unclear, bed studies have shown that changes in the effectiveness of monoamine neurotransmitters (such as norepinephrine, dopamine, and serotonin) and differences in receptor regulation differ from the disease-related.

Other factors such as psychosocial factors, such as social isolation, stressful living environment, and lack of support/trust relationships also increase the risk of depression.

A systematic literature analysis (meta-analysis, including 4 randomized controlled trials, a total of 948 patients with severe depression) pointed out that Vitamin D supplementation had a good effect on depression scores, and the pooled mean effect size was 0.58, representing Moderate impact.

*Conclusion: For patients with severe depression, supplementation with Vitamin D can bring positive help, but it is limited by the small sample size and methodological bias, and more research is needed to corroborate.

15. Is vitamin D good for osteoarthritis?

Osteoarthritis is one of the most devastating chronic diseases, mainly affecting the three parts of the knee joint (medial, lateral, and patellofemoral joints). The disease takes about 10 to 15 years from scratch to cause disability. Risk is comparable to cardiovascular disease.

Although the population usually associated with the disease is the elderly, athletes and adolescents are also susceptible, and aging, injury, professional activity, genes, gender, lower limb dysplasia, and obesity seem to be the most common causes.

A systematic literature review and meta-analysis (including 4 randomized controlled trials with a total of 1130 participants) pointed out that compared with placebo, taking Vitamin D had statistically significant pain control in patients with knee osteoarthritis Sexual improvement (but not much).

In addition, no changes were observed but the tibial cartilage volume or joint space width.

*Conclusion: Vitamin D supplementation has no clinical significance for pain control or structural progress in patients with knee osteoarthritis, and needs more large-scale long-term trials to further verify.

16. Vitamin D benefits type 2 diabetes

Diabetes is a major health problem that causes serious complications and disabilities around the world. It is a chronic progressive metabolic disorder characterized by hyperglycemia, mainly due to the lack of absolute (type 1 diabetes) or relative (type 2 diabetes) insulin hormones.

It is generally believed that a Western-style diet with high calories and a sedentary lifestyle are the main causes of type 2 diabetes.

A literature review and Meta-Analysis (including 71 observational studies) pointed out that in patients with diabetes and non-diabetes, Vitamin D status was found to be significantly negatively correlated with blood glucose levels. If Vitamin D deficiency (hypovitaminosis D) Will increase the risk of high blood sugar and type 2 diabetes.

A literature meta-analysis (including 28 randomized controlled trials) pointed out that for patients with prediabetes or high-risk groups of diabetes, supplementation with Vitamin D (average daily dose of 3500 IU for 6 months) can improve blood glucose control (HbA1c and fasting Blood glucose) and reduce insulin resistance, but the effect may vary depending on age, calcium intake, Vitamin D deficiency, and serum 25(OH)D level status.

A literature review and meta-analysis (including 20 randomized controlled trials) pointed out that for patients with type 2 diabetes, Vitamin D supplementation can significantly improve serum 25(OH)D levels and insulin resistance index (HOMA-IR), and the improvement was particularly significant: non-obese subjects, Middle Eastern populations, lack of Vitamin D, better baseline blood glucose control, short-term, high-dose (daily dose of 2000 IU) patients were the most significant.

*Conclusion: Vitamin D deficiency will increase the incidence of type 2 diabetes, and under some conditions, additional supplements can improve blood glucose control of existing patients and reduce the incidence of high-risk groups.

17. Vitamin D reduces preterm birth

Premature delivery is usually defined as any delivery before 37 weeks of pregnancy. The current global premature birth rate is 11.1%, but it varies with regions and ethnicities. In some parts of Africa, the premature birth rate is more than 15%, some European countries have a premature birth rate of 5-6%, and some parts of East Asia may have lower premature birth rates.

The causes of premature birth are complex, however, some predisposing factors have been identified, including prenatal bleeding, placental abruption, uterine bloating, cervical insufficiency, hormonal changes, bacterial infections, and inflammation.

A literature review and meta-analysis (including 6 randomized controlled trials and 18 observational studies) pointed out that the lack of 25-OHD in the maternal blood (25-OHD value less than 50) is associated with an increased risk of preterm delivery, and pregnancy Vitamin D supplementation alone can reduce the risk of preterm birth by 43%.

The underlying mechanism is related to Vitamin D improving premature birth-related predisposing factors, such as infection, inflammation, and oxidative stress.

*Conclusion: The lack of Vitamin D in pregnant women will increase the risk of preterm birth, and supplementing Vitamin D alone can reduce the risk value.

18. Vitamin D benefits polycystic ovary syndrome

Polycystic ovary syndrome is the most common female endocrine disorder, and the prevalence of women of childbearing age is close to 5% to 10%.

The disease is characterized by elevated adrenal androgens secreted by the ovaries. Common symptoms include hirsutism, irregular menstruation, acne, anovulatory infertility, hair loss, and polycystic ovary, accompanied by other metabolic abnormalities, including dyslipidemia, insulin resistance, Hypertension, etc.

A meta-analysis of literature (including 17 studies) pointed out that the blood 25OHD concentration and insulin sensitivity of patients with polycystic ovary syndrome were significantly lower. In addition, the supplement of Vitamin D lacks the response (the serum parathyroid hormone concentration, insulin resistance, and insulin sensitivity have not changed).

Another meta-analysis (meta-analysis, including 9 randomized controlled trials, a total of 502 patients with polycystic ovary syndrome) pointed out that Vitamin D supplementation may be beneficial to follicular development (with more dominant follicles) and menstrual cycle regulation.

A recent meta-analysis of the literature (including 7 randomized controlled trials) pointed out that Vitamin D supplementation in women with polycystic ovary syndrome can significantly reduce high sensitivity C-reactive protein and malondialdehyde, and increase the total antioxidant capacity (total antioxidant capacity) level (but the total nitric oxide glutathione (GSH) content has not changed significantly).

*Conclusion: Compared with the average person, patients with polycystic ovary syndrome have a lower blood 25OHD concentration, which may be positively helpful to the condition through additional supplementation.

19. Is Vitamin D beneficial to older people’s athletic ability (walking speed)?

Walking speed is a simple, objective, and overall lower limb neuromuscular function and physical performance index that can reflect the health, disease, fitness, and emotional state of the subject.

As you age, walking speed decreases, and slower walking speed increases the risk of falls, hospitalization, and subsequent decline in physical and cognitive abilities. It can also be used to predict survival rates.

Gait speed over 1.0 m/s is an important indicator of community life and participation, reflecting the ability of daily life activities.

In contrast, gait speeds less than 0.6 m/s are considered to be unusually slow and are related to the decline of independent functions.

A systematic literature review and meta-analysis (including 24 observational studies, with participants ranging from 51 to 4100 seniors) pointed out that the measured value of Vitamin D in the blood, 25OHD concentration, is obviously related to the walking speed of the elderly, compared with For those with normal values, subjects with severe deficiency, deficiency, and deficiency of Vitamin D walk significantly slower.

*Conclusion: The concentration of 25OHD is positively correlated with the walking speed of the elderly. The walking speed of those who are lacking or insufficient is significantly slower, but more research is still needed to confirm whether supplementation can bring improvement effects.

20. Does Vitamin D improve lower back pain?

Low back pain, also known as low back pain, is a common disease. Up to 84% of adults will experience it in their lifetime. It is the second leading cause of work loss. In the United States, there is a $50 billion spend related to it.

Low back pain may be caused by many potential factors, such as nerves, muscles, fascia structures, bones, joints, intervertebral discs, and organs in the abdominal cavity.

The acute attack usually refers to the duration of less than 2 to 4 weeks, the subacute is 12 weeks, and the chronic refers to more than 12 weeks.

A Meta-Analysis (including 8 clinical trials, 3,534 participants) pointed out that compared with any intervention (placebo, non-intervention, or other pharmacological intervention), taking Vitamin D did not improve the symptoms of lower back pain. It has a significant effect, and the results have not changed even after stratified analysis (back pain type, supplement form).

*Conclusion: Vitamin D supplementation did not bring significant benefits to lower back pain, and due to the small sample size and heterogeneity of the study, further confirmation is needed.

21. Vitamin D benefits atopic dermatitis

Atopic dermatitis is a chronic or recurrent inflammatory skin disease characterized by pruritic papules (with serous exudates), sometimes the epidermis will peel off and appear mossy, and usually have a curved distribution.

Although the pathophysiological factors of atopic dermatitis are not fully elucidated, it is currently believed to be the result of a combination of epidermal barrier dysfunction, immune disorders, and environmental factors. Common triggers include food allergies, heat, sweating, anxiety, depression, and infection.

An observational study found (targeting 60 patients with atopic dermatitis) that Vitamin D levels were negatively correlated with the severity of atopic dermatitis in children.

A meta-analysis (including 4 randomized controlled trials) pointed out that compared with placebo, Vitamin D supplementation has a potentially important role in improving the symptoms of atopic dermatitis, and can be considered as a safe and acceptable treatment plan.

The underlying mechanism may be related to the immunomodulatory effects of Vitamin D, on the formation and recovery of the skin barrier, reducing the transdermal water loss, and promoting the production of antibacterial peptides from keratinocytes, macrophages, and neutrophils.

*Conclusion: For patients with atopic dermatitis with insufficient Vitamin D, additional supplements can help relieve symptoms. However, due to genetic, environmental, and other confounding factors, more accurate experiments need to be designed to further verify.

22. Vitamin D is beneficial for blood pressure regulation

Hypertension is the most common cardiovascular disease of middle-aged and middle-aged people, and early detection and self-management are the keys to the prognosis of the disease.

Vascular and organ complications related to hypertension include stroke, retinopathy, coronary heart disease/myocardial infarction and heart failure, proteinuria, and renal failure, as well as changes in vascular disease and atherosclerosis, etc.

A meta-analysis of literature (including 30 randomized controlled trials, 4744 participants) pointed out that the effect of Vitamin D3 supplementation on blood pressure will vary according to dose, treatment plan, test time and population composition, of which daily dose The most antihypertensive benefit is used by ethnic groups over 800 IU and aged over 50 (whether healthy or hypertensive).

*Conclusion: Supplemental Vitamin D3 may have a blood-pressure-lowering effect on middle-aged and above ethnic groups, but more experiments are still needed to further verify.

23. Vitamin D benefits female hair loss

Female pattern hair loss usually refers to diffuse non-scarring hair loss. The main symptom of sparse hair volume at the top of the head is less affecting the forehead hairline and the age of good hair. For women aged 20 to 30 (12%) and women over 70 (55%).

The main causes of female pattern hair loss may be related to genetic susceptibility, iron deficiency and hormonal imbalance often referred to as female pattern male baldness.

A case-control study (for 45 female pattern hair loss patients) found that those with lower levels of Vitamin D3 in the blood had a higher incidence of female pattern hair loss than healthy people.

*Comment: Vitamin D3 deficiency is associated with female pattern hair loss. More research is needed to confirm whether supplementation can bring benefits.

24. Vitamin D reduces the chance of cognitive dysfunction

Cognitive function is unique to a few species and can interact with the outside world, such as memory, language, object recognition, planning, etc. Any kind of function, such as disappearance or gradual degradation, is called cognitive impairment.

If there are more than two kinds of cognitive impairments, and it seriously affects life and workability, it can be defined as dementia.

A meta-analysis of literature (meta-analysis, including 7 studies, 6068 participants) pointed out that insufficient concentration of Vitamin D in the blood (25OHD ≤20 ng) will significantly increase the chance of cognitive impairment in the elderly, especially in semantic memory and time direction (25OHD greater than 20 ng mL can reduce the risk of cognitive impairment by 14.1%).

The underlying mechanism may be related to Vitamin D’s ability to protect neural networks, regulate neurotrophic factors, regulate inflammation, promote neuronal vitality and function, and reduce amyloid plaque accumulation.

*Conclusion: According to the Asian Population Survey, insufficient Vitamin D concentration in the blood is positively associated with cognitive dysfunction.

25. Vitamin D reduces cold events: acute respiratory infection

Respiratory tract infections are mainly caused by bacterial, viral, or fungal infections of the respiratory tract (nose, throat, and lungs). Due to their characteristics of easy transmission and high incidence, they are the most important items in public health issues.

Symptoms can range from mild common cold, laryngitis, pharyngitis, tonsillitis, acute rhinitis, acute sinusitis, acute otitis media, to potentially fatal acute bronchitis, pneumonia, and bronchitis.

A systematic literature review and meta-analysis (including 25 controlled studies with a total of 11321 participants) indicated that Vitamin D supplementation can help reduce the risk of acute respiratory infections.

And in subgroup-analysis, it is found that the protective effect is more obvious for those who regularly add habit (and especially the objects with 25-hydroxyvitamin D less than 25 nmol/L).

*Summary: Daily regular supplementation of appropriate doses of Vitamin D can help reduce the incidence of acute respiratory infections.

26. Vitamin D improves breast cancer prognosis and mortality

Breast cancer is the first invasive malignant tumor among female cancers. The main risk factors include first-degree relative genetics, breast tissue density, previous benign breast biopsy results, oral contraceptive use, childbearing age, etc., and having individual factors dating increases by 1 to 2 Double the risk of cancer.

The relationship between Vitamin D deficiency and cancer has been confirmed by many studies, and a recent disease prospective cohort study also pointed out that the concentration of Vitamin D in the blood (25-hydroxyvitamin D) is in the front third of breast cancer patients, Will increase the overall survival rate by about 30% compared with the latter third.

The related effect of improving the survival rate is more obvious in premenopausal women, showing that Vitamin D plays an important role in cancer prevention and prognosis.

27. Vitamin D is beneficial for fatigue

Fatigue seems to be commonplace for busy modern people, but if left unchecked and the underlying cause is not thoroughly identified, it will lead to various physical and mental disorders for a long time.

And everyone must have their own common anti-fatigue therapy, such as bathing, listening to music, eating food, massage, etc. Unfortunately, most of these have no scientific basis.

A double-blind controlled study found that (for 4 weeks, 120 subjects were in good health but lacked Vitamin D/25(OH)D < 20 μg/L), compared with placebo, Vitamin D therapy can significantly improve The subject’s fatigue assessment scale.

That is, the degree of improvement in fatigue is greater. And these changes are also related to the increase of 25(OH)D concentration in the blood.

28. Vitamin D is beneficial for colorectal irritability

Irritable bowel syndrome is a disease of abnormal bowel function, the main features are abdominal pain, bloating, diarrhea, constipation, and intestinal motility disorders.

According to the survey, the prevalence of women with this disease is twice that of men. The more economically developed the country is, the higher the incidence is, reaching about 10% of the total population.

Due to the complex causes (psychological factors, abnormal bowel movements, intestinal infections, inflammation, immune disorders, etc.), some clinical drugs often fail to achieve the desired results, so many alternative therapies are born.

A double-blind controlled study (6 months, 90 samples) pointed out that Vitamin D (50 000 IU, taken every other week) can help improve the symptoms of patients with colorectal irritability (including abdominal pain, flatulence, abdominal distension, Overall gastrointestinal symptoms).

In addition to symptom improvement, IBS severity score system (IBS severity score system) and quality of life score (IBS-QoL scores) also have significant improvements (compared to placebo).

29. Vitamin D reduces the incidence of schizophrenia

Schizophrenia is a brain disease related to mental disorders such as cognition, emotion, and thinking. Patients often have unrealistic thoughts and behaviors, which affect interpersonal relationships, work, and self-care abilities. Young ethnic group, so it is also called an adolescent mental disorders.

Studies have shown that people with Vitamin D deficiency have a higher incidence of schizophrenia (the underlying mechanism may be related to Vitamin D regulating PRODH/proline dehydrogenase and reducing the concentration of proline).

*Proline is a neuroregulatory substance. Excessive concentration is positively correlated with decreased IQ, cognitive impairment, and schizophrenia recurrence rate and hospitalization.

Another study on women also found that a higher intake of Vitamin D in the diet can significantly reduce psychotic-like symptoms by 37%.

30. Vitamin D improves sleep disorders (for those with lower Vitamin D concentration)

Sleep disorders have almost become an epidemic in the past 40 years, and there are thousands of reasons behind the failure to sleep, and there is no effective and no side-effect cure to date.

The only discovery is that long-term sleep disorders can cause many diseases, such as high blood pressure, cardiovascular disease, depression, chronic pain, etc.

Some studies have pointed out that sleep disorders may also be related to Vitamin D deficiency, and related mechanisms may be related to Vitamin D’s ability to exert hormonal effects and combine with brain receptors to achieve the effect of regulating sleep, but more reports are needed to verify.

Another study also found that Vitamin D supplementation has the effect of improving sleep, but this experiment is aimed at patients with chronic pain.

31. Vitamin D affects in-patient mortality

The vast majority of people only learn about the disease and related knowledge after getting sick. Although hospital care can save your life, you usually do not encounter emergencies. Whether you want to go to the hospital is usually not easy to decide. Especially the elderly usually have a fixed impression of the hospital and feel that it is difficult to get out of the hospital.

The New England Journal of Medicine has published a paper (NEJM) exploring the association between Vitamin D concentration in the body and mortality in patients in intensive care units.

It was found that Vitamin D deficiency patients have a mortality rate of up to 45% (normal values ​​are only 16%), which shows that Vitamin D deficiency can actually increase the total mortality rate of emergency hospitalized patients by 3 times.

In addition, there have been continuous studies to confirm this argument recently. A study of 135 patients in intensive care units found that if the Vitamin D concentration is lower than 12 ng/mL, there is a 32.2% risk of death, while those above this value are only 13.2%, which is nearly 2.5 times Gap.

Despite this, there are still studies that indicate that high-dose supplementation of Vitamin D during hospitalization does not bring immediate protection. This shows that to achieve the above-mentioned mortality reduction effect, it must be established on a continuous basis, that is, Vitamin D must be maintained in the body.

32. Vitamin D reduces the chance of wheezing and wheezing in future generations

Wheeze is a high-pitched whistling sound. It is the most common symptom of asthma in children five years and younger. It occurs when the small airway narrows due to bronchospasm, swollen mucosa, excessive secretions, or inhalation of foreign bodies, Due to severe airway obstruction, usually only heard when exhaling.

Wheezing in young children may also be caused by inflammation or anatomical abnormalities, so not all wheezing bronchitis will develop into wheezing.

A literature review and meta-analysis (including 7 studies with a total of 6,068 participants) pointed out that the Vitamin D intake of pregnant women during pregnancy is associated with a non-linear U-shaped curve of wheezing and wheezing events and occurrence of offspring, the daily dose is around 800 IU, which has the most protective effect.

*Conclusion: Vitamin D intake during pregnancy may help reduce the incidence of wheezing and wheezing in future generations.

How to supplement Vitamin D? How to determine the dosage and intake?

How much Vitamin D is required depends on many factors. These factors include age, race, latitude, season, sunshine, clothing, etc.

According to the Institute of Medicine (IOM) of the National Academy of Sciences, the current recommended daily intake of Vitamin D is 400 IU to 800 IU or 10-20 micrograms, but this value is too low for adults.

Most young adults increase the risk of Vitamin D deficiency due to insufficient sun exposure and excessive use of sunscreen.

Therefore, most studies have shown that in order to achieve an optimal serum level of 25 (OH) D above 30 ng/ml, at least 1000 IU or 1500 to 2000 IU needs to be supplemented daily.

When to eat Vitamin D?

A study of the relationship between the amount of fat in the diet and the absorption rate of Vitamin D supplementation found that compared with the control group without a fat diet, the plasma Vitamin D3 spike level with the fat diet can be about 32% higher, but the fat form will not Affect absorption.

This means that Vitamin D supplementation can be done at any time, and taking it with meals can increase the absorption rate.

Are there any side effects of Vitamin D supplementation? What is an overdose?

Although most people take Vitamin D supplements without any problems, an overdose is also possible.

According to the Institute of Medicine, 4000 IU is the safe upper limit of daily Vitamin D intake for adults. However, daily doses up to 10,000 IU have not been shown to be toxic to healthy individuals.

But daily intake of 40,000 to 100,000 IU (1000-2500 micrograms) for more than 1 month has been shown to be toxic to humans.

This is 10-25 times the upper limit of the recommended dose. The blood level of 25(OH)D, which generally produces Vitamin D toxicity, is usually higher than 150 ng/ml (375 nmol/L).

That is, taking Vitamin D causes toxicity, usually when taking 40,000 IU per day for several months or longer, or when taking a large dose at a time.

When the level of 25(OH)D is too high, this will cause the blood calcium level to rise, resulting in a disease called hypercalcemia.

Early symptoms of hypercalcemia include nausea, vomiting, diarrhea, constipation, loss of appetite, and fatigue. Other symptoms include: muscle weakness or pain, excessive thirst, altered consciousness, high blood pressure, renal tube calcification, renal failure, or hearing loss can also occur.

Vitamin D’s toxicity is usually reversible, as long as avoiding sun exposure and stopping all diet and supplement intake, it can be recovered, but the serious cases are renal failure and arterial calcification (usually irreversible).

Precautions for taking vitamin D (5 major contraindications)

1. In some rare diseases, even if your Vitamin D content is very low, and you do not take too much Vitamin D, you may still suffer from hypercalcemia. For patients with the following diseases, it is best to confirm with your doctor before supplementing with Vitamin D before use.

These diseases include primary hyperparathyroidism, granulomatous diseases, sarcoidosis, tuberculosis, lymphoma.

2. Pregnant women or breastfeeding women should not take too much Vitamin D (the daily dose should not exceed 4000 IU), which may lead to hypercalcemia, infantile epilepsy, stunting, etc.

3. Do not use in combination with cholesterol-reducing Statin drugs (such as Lipitor), high blood pressure drugs calcium channel blockers (may affect drug absorption).

4. Do not use in combination with psoriasis medication Calcipotriene or arrhythmia medication (Digoxin) (may cause hypercalcemia).

5. Long-term use of steroid drugs (Corticosteroids) may lead to osteoporosis, patients should pay special attention, or discuss the possibility of calcium or Vitamin D supplementation with the doctor.

Drugs that may reduce the absorption of Vitamin D (If you take these drugs, please discuss with your doctor how to supplement them)

Antiepileptic drugs, antacids, antibiotics (Rifampin), diet pills (Orlistat), hypolipidemic cholate sequestrants (Bile acid sequestrants)

Drugs that may enhance Vitamin D absorption

Diuretics (Thiazide), estrogen, tuberculosis drugs (Isoniazid)

Which Vitamin D2 or D3 supplement has a higher absorption rate?

Vitamin D is a type of fat-soluble Vitamin (others have A, E, and K). Vitamin D in nature is divided into the following two forms:

Vitamin D2 (ergocalciferol): Mainly present on plants, it is produced by ergosterol through photosynthesis. The most abundant content is mushrooms and other fungi. It is also often added to fortified foods, such as cereal or milk powder.

Vitamin D3 (cholecalciferol): It is mainly present in animals and is generated by the reaction of subcutaneous dehydrocholesterol with ultraviolet rays in sunlight.

A meta-analysis (including 8 randomized controlled trials) pointed out that the effect of supplementing Vitamin D3 to increase the concentration of 25(OH)D in the blood is significantly better than Vitamin D2.

Another study also pointed out that compared with D2, the effect of D3 to increase the concentration of 25(OH)D is not only 87% higher, but also the rate of degradation in the blood is slower after stopping taking it (meaning the peak concentration can be maintained longer), so To add extra, choose the D3 format will have advantages.

* 25(OH)D or 25-hydroxyvitamin D is the main parameter in the medical community to measure the concentration of Vitamin D in the blood.

How to know the lack of Vitamin D?

Vitamin D deficiency can only be found through blood tests. Blood tests can measure the storage level of Vitamin D, using 25-hydroxyvitamin D, which is the value of 25(OH)D.

According to the Institute of Medicine, the following values ​​determine your Vitamin D status.

Severe deficiency: less than 12 ng/ml (30 nmol/l)

Insufficient: level between 12-20 ng/ml (30 – 50 nmol/l)

Enough: between 20 – 50 ng/ml (50 – 125 nmol/l)

High: greater than 50 ng/ml (125 nmol/l)

May cause poisoning: greater than 150 ng/mL, or 375 nmol/L

However, some studies have found that Vitamin D blood levels of 30 ng/ml (75 nmol/l) are more helpful in preventing fractures, falls, and certain cancers.

The main (natural food) source of Vitamin D?

In general, the food sources of Vitamin D are very scarce, and the more common ones listed below

Cod liver oil: 1 spoon (tablespoon) contains 1,360 IU (34 mcg) or 227% of RDA.

Swordfish or Swordfish is cooked: 3 ounces (85 grams) contains 566 IU (14.2 mcg) or 94% of RDA.

Salmon (cooked): 3 ounces (85 grams) contains 447 IU (11.2 mcg) or 74.5% of RDA.

Canned tuna: 3 ounces (85 grams) contains 154 IU (3.9 mcg) or 26% of RDA.

Beef liver cooked: 3 ounces (85 grams) contains 42 IU (1.1 mcg) or 7% of RDA.

Egg yolks: 1 egg contains 41 IU (1 mcg) or 7% of RDA.

Mushrooms: 1 cup contains 32.8 IU (0.8 mcg) or 5.5% of RDA.

How long does it take to get enough Vitamin D under the sun?

Sunbathing is the best way to get Vitamin D without side effects, and never exceed the body’s required dose.

Compared with Vitamin D obtained from food or supplements, the duration of Vitamin D produced through the skin in the human circulation is at least 2 to 3 times longer.

Each person’s sun exposure time must be adjusted according to various external and internal conditions (such as time of day, the season of the year, latitude, aging, use of sunscreen, and skin pigmentation) when insufficient This can be achieved by additional supplements.