Month: April 2021

You don’t have to look far to find claims that taking vitamin D supplements is great for your health. It’s supposed to be good for everything from preventing cancer and dementia to avoiding infections and heart disease.

Unfortunately, many supposed benefits of vitamin D supplements remain unproven. Yet, millions of people take vitamin D regularly, thinking it will help prevent a wide range of illnesses, including certain autoimmune conditions. But does it? A new randomized, controlled study published in TheBMJ looks closely at that question.

Why would vitamin D prevent autoimmune disease?

Although the cause of most autoimmune disease 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.

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

• 2,000 IU of vitamin D or an identical placebo (inactive pill) daily. (This is higher than the recommended daily amount for adults, but lower than the upper limit of 4,000 IU.)
• 1,000 mg 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?

The answer may depend on where you heard or read about the BMJ study. It’s true that the researchers found that adults taking vitamin D supplements had a lower risk of developing autoimmune disease. But here’s what some of the more enthusiastic news headlines said:

• Vitamin D supplements really do reduce 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)

Sounds great, right? But is it true?

What does a closer look at the study tell us?

The researchers reported that

• 123 people taking vitamin D developed autoimmune disease, compared with 155 people in the placebo group. This represents a 22% reduction. That sounds like a lot, but the actual decrease in risk for developing an autoimmune disease fell from about 12 people in 1,000 to 9.5 people in 1,000.
• Rheumatoid arthritis, polymyalgia rheumatica, and psoriasis were the most common conditions. 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.
• Those assigned to receive omega-3 fatty acids did not have a lower risk for confirmed autoimmune disease.
• Side effects were minor and similar in those taking supplements and those taking placebo.

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.

In addition, the study only included older adults (average age 67). This is important because some of the 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, I’d say no. For one thing, these findings need to be confirmed by other independent researchers. And despite overly enthusiastic headlines, 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? Based on current research that’s not clear yet, though I think it’s best to keep an open mind. We may find vitamin D does little for the average person but is highly beneficial for others; the trick is figuring out who is most likely to benefit. For example, perhaps supplemental vitamin D will be especially helpful for people who have a strong family history of certain autoimmune diseases.

Right now, we have the latest chapter in the story of vitamin D. Future research may reveal that a different dose or formulation of vitamin D might be particularly beneficial. Perhaps most importantly, this study and others to come could provide a better understanding of the role of vitamin D in the development of autoimmune diseases.

Follow me on Twitter @RobShmerling

About the Author

Robert H. Shmerling, MD, Senior Faculty Editor, Harvard Health Publishing

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School. As a practicing rheumatologist for over 30 years, Dr. Shmerling engaged in a mix of patient care, teaching, and research. His research interests center on diagnostic studies in patients with musculoskeletal symptoms, and rheumatic and autoimmune diseases. He has published research regarding infectious arthritis, medical ethics, and diagnostic test performance in rheumatic disease. Having retired from patient care in 2019, Dr. Shmerling now works as a senior faculty editor for Harvard Health Publishing. View all posts by Robert H. Shmerling, MD

Some people may be cautious when it comes to using oils in cooking or with their food. Eating fat with meals conjures thoughts of high cholesterol and, well, getting fat. The fact that some fats are labeled as “bad” adds to the confusion and misconception that all fats are unhealthy.

But that isn’t the case.

“It’s important to consume oils,” says Shilpa Bhupathiraju, assistant professor of medicine at Harvard Medical School and assistant professor of nutrition at Harvard’s T.H. Chan School of Public Health.

Oils and fats contain essential fatty acids — omega 3s and 6s, in particular — that are part of the structure of every single cell in the body, says Walter Willett, professor or epidemiology and nutrition at the Harvard T.H. Chan School of Public Health. They’re the building blocks of hormones, help decrease inflammation, and lower bad cholesterol and blood pressure. Oil also provides taste and satiety.

The key is knowing the right kind to use. It’s easier when you’re cooking at home, a little trickier when you’re eating out and you can’t control every step in the process. But it’s not just about picking the healthiest oils. They play a part in a healthy diet when they’re part of an eating plan that minimizes processed foods, simple carbohydrates, and sugar.

Healthy and not-so-healthy oils

In general, Willett says that the healthiest oils are liquid and plant-based. The one that comes to mind first is olive oil, and for good reason. “It’s stood the test of time,” he says. It helps lower blood cholesterol and provides antioxidants, and extra virgin is the ideal version, as it’s the first pressing and least refined.

After that, corn, canola, sunflower, safflower, and soybean all fall into the healthy column. The last one wasn’t always considered a healthy choice because it used to be hydrogenated, but now it’s in a natural state and a good source, says Willett.

On the unhealthy side, there’s lard, butter, palm oil, and coconut oil. The commonality is that they come in a semi-solid state and have a high level of saturated fat. The consumption of that fat increases LDL cholesterol (the bad kind), and has been associated with increased risk for cardiovascular disease and diabetes.

Willett says part of the challenge is cultural. Northern European tradition is based on eating animals and animal fats, and those fats, like butter and lard, come in solid form. The Southern European approach, like the Mediterranean diet, is based on plant-based oils, particularly olive.

While saturated fats provide none of the above-mentioned health benefits, they don’t have to be avoided entirely, just minimized to 5% of your diet, says Willett. For example, if you typically consume 2,000 calories a day, only 100 should come from saturated fats.

Eating out versus at home

If you’re eating at home and you’re using healthy oils, there is less concern about consuming the wrong fats or too much. Whether you’re frying, sautéing, or dressing a salad, you’re in control of all the factors. Using too much oil isn’t such a concern, Bhupathiraju says, since people usually regulate their intake through knowing when something will taste too oily.

Frying, in general, is often a worry, but it’s not necessarily unhealthy. It’s more about what’s being fried. Cheese, a saturated fat, wouldn’t be a great choice, but zucchini wouldn’t be bad, as Bhupathiraju says.

The concern with fried foods, and eating out in general, is what kind of oil is being used and how. With deep fryers, if the oil isn’t regularly changed, it repeatedly gets reheated and trans fats are created. These can produce inflammation in the body, which can lead to heart disease, type 2 diabetes, and contributes to the breakdown of cell membranes.

The easiest move is to avoid eating all fried foods. But Willett says that, again, that’s not always necessary. The use of trans fats was prohibited in 2018, so it’s likely a restaurant is using a healthier oil. Even so, eating fried foods occasionally isn’t too harmful.

Focus on maintaining a healthy diet, with good oils

Willett says that people get the majority of their calories from two sources — fats and carbohydrates — and “what’s important is both should be healthy,” he says.

When you eat healthy carbs and fats, you don’t have to worry about how much you’re eating of either. “The ratio doesn’t make much difference. They’re both healthy,” he says. The focus in on overall eating. A healthy diet can consist of mostly whole grains like brown rice, steel-cut oats, wheat berries, and quinoa. The less something is milled and made into a powder, the more slowly it will release into the body, preventing sudden spikes in blood sugar.

While low-fat diets had some popularity in the 1990s, low-fat products aren’t healthier. Willett says that research has shown that low-carb diets are more effective for weight loss than low-fat ones, and that low-fat diets are not more effective for weight loss than higher-fat ones.

The best approach to eating well is the science-backed recommendation of having lots of colors on your plate. Orange, yellow, green, and red foods supply various antioxidants and phytochemicals that may be protective to the body. When you compose your diet like this, chances are you’ll eat more slowly and consume fewer empty calories, Bhupathiraju says.

“Enjoy fats,” Willett says. “Good olive oil is good for you. It will help you enjoy the salad and make the eating experience and eating of vegetables more enjoyable.”

About the Author

Steve Calechman, Guest Contributor

Steve Calechman is a contributing editor for Men’s Health, a writer for MIT’s Industrial Liaison Program, and his work has appeared in The Boston Globe Magazine, Greentech Media, Fatherly, and BabyCenter. For over 25 years as a journalist, he’s written about everything from handling stress like an Alaska bush pilot to computational neuroscience to how to change your mind mid-sentence with your child. If you’d like to visit his website at stevecalechman.com, he won’t try to stop you. View all posts by Steve Calechman