- Vitamin D has assumed legendary credibility and assumed potency over the years.
- During the pandemic, it was claimed that those COVID-19 patients who were low on Vitamin D fared worse than those who were not deficient in the sunshine nutrient.
- A Harvard professor takes a close look at the recent claim that Vitamin D supplements can prevent autoimmune disease.
Sources of Vitamin D:
You can get most of this from food sources like oily fish (salmon, sardines, herring and mackerel), red meat, liver, egg yolks, and in some countries like the US /UK where foods such as some fat-spreads and breakfast cereals are fortified.
After the right diet, exposure and doing a bit of your walking and working in sunshine/sunlight is good to synthesise calcium and phosphates in the body that are needed to keep bones, teeth and muscles healthy.
But too much of any good thing is a bad thing. Too much vitamin D can cause an abnormally high blood calcium level, which could result in nausea, constipation, confusion, abnormal heart rhythm, and even kidney stones.
Unless you overdose on cod liver oil, food sources cannot cause vitamin D toxicity and nearly all vitamin D overdoses come from supplements. What damage can Vitamin D toxicity do? It causes a buildup of calcium in your blood (hypercalcemia). The patient suffers nausea and vomitting, weakness, and frequent urination. Untreated on time, this excess Vitamin D in the blood can progress to bone pain and kidney problems, such as the formation of calcium stones.
Vitamin D is considered a ‘Magic Pill’ – well, almost!
But look all around you. The way vitamin D is being touted as the cure-all for most ailments and a preventive fix for a host of health conditions, most people believe that taking vitamin D supplements is great for your health; that it will help prevent cancer and dementia, help defeat infections and heart disease.
Is that true? Is Vitamin D our fortification against autoimmune illnesses?
Dr Shmerling cites a new randomized, controlled study published in the BMJ that looks closely at that question.
Why would vitamin D prevent autoimmune disease?
Although the cause of most of the known autoimmune diseases is largely unknown, the leading theory is that the regulation of the body’s immune system goes awry. The immune system normally defends the body from invaders such as infections and helps repair damaged tissues. When an autoimmune condition develops, the immune system attacks its host. For example, with rheumatoid arthritis, immune cells attack joints, lungs, and other parts of the body.
Yes, Vitamin D does “talk” to the immune system:
Research has shown that vitamin D can interact with immune cells, affect genes that regulate inflammation, and alter the response of the immune system. So it makes sense to investigate whether supplemental vitamin D is an effective way to treat or prevent autoimmune disease.
The BMJ study drew on data gathered during a large trial published several years ago.
More than 25,000 older adults were randomly assigned to take:
- Either a 2,000 IU of vitamin D or an identical placebo dose (inactive pill) daily. (This is higher than the recommended daily amount for adults but lower than the upper limit of 4,000 IU.)
- Or a 1,000 mg dose of omega-3 oil or an identical placebo daily.
After an average of five years, new diagnoses of autoimmune disease among study participants were tallied.
What did the new study find?
Dr Shmerling points out that too much was read into the findings. Yes, researchers did find that adults taking vitamin D supplements had a lower risk of developing autoimmune disease. But some publications just went overboard with their conclusions and headlines, feels Dr Shmerling. He points out a few headlines that read:
- Vitamin D supplements really do reduce the risk of autoimmune disease (New Scientist)
- Taking Vitamin D Daily Can Help Prevent This Disease, New Study Says (Eat This, Not That!)
- Taking vitamin D and omega-3 fish oil supplements every day cuts your risk of developing arthritis by 22%, study suggests (Daily Mail)
Dr Shmerling suggests that though all these headlines make it sound like a miraculous remedy, a closer look at the study tells a different story.
Looking closely, the study seems to have shortcomings and flaws:
- No single autoimmune disease was reliably prevented by vitamin D supplementation.
- Only when the numbers of all the autoimmune diseases were combined did researchers see a benefit.
- The benefit of vitamin D was more obvious when only the final three years of the study were analyzed. This suggests that it takes a while to benefit from a daily supplement.
- This randomized study is among the best to explore the impact of vitamin D supplementation on the risk of developing autoimmune disease.
- Yet the study relied on self-reported cases, later confirmed by medical record review. So it’s possible that some cases of autoimmune disease were overlooked.
Dr Shmerling points out that most common autoimmune diseases, such as lupus and rheumatoid arthritis, typically begin in early adulthood. The results might have been different if the study had included younger participants.
Should we all be taking vitamin D supplements?
Based on this study, Dr Shmerling says, “I’d say no. For one thing, these findings need to be confirmed by other independent researchers. And despite overly enthusiastic headlines, the actual risk reduction was just 2.5 cases out of 1,000. Hundreds of people would need to take vitamin D daily for years to prevent a single case of autoimmune disease. Vitamin D can interact with other medicines, and taking high amounts of vitamin D can be harmful.”
The Bottom Line:
Is vitamin D a safe, all-natural wonder drug that can prevent or treat a litany of diseases? Dr Shmerling says it’s best to keep an open mind. Perhaps supplemental vitamin D will be especially helpful for people who have a strong family history of certain autoimmune diseases. Meanwhile, we suggest that you eat the right foods, stay active and take a safe and significant amount of sun on your body and yes, consult your doctor before adopting any well-meaning health-related advice – whether here or elsewhere – by anyone else.
Disclaimer: Tips and suggestions mentioned in the article are for general information purposes only and should not be construed as professional medical advice. Always consult your doctor or a dietician before starting any fitness programme or making any changes to your diet.