Vitamin D is a fat-soluble, rather than water-soluble, vitamin — so when you get it through your diet, you’ll best absorb it alongside a fat-containing food, such as almonds, peanut butter, or avocado. The vitamin is important for your health: Research suggests that it may help with everything from athletic performance to heart disease, and may even help protect against type 2 diabetes.
What Does Vitamin D Do for Our Bodies and Our Health?
Vitamin D plays many important roles in the body and helps you maintain healthy bones, joints, and teeth, as well as a well-functioning immune system. “Vitamin D aids in the absorption of calcium in the body to promote bone growth,” notes Erin Palinski-Wade, RD, CDE, author of The 2-Day Diabetes Diet: Just 2 Days a Week and Dodge Type 2 Diabetes, who is in private practice in Franklin, New Jersey. “Some observational studies suggest vitamin D may also play a role in the prevention of certain diseases and disorders, such as diabetes.” The sunshine vitamin may also help keep your ticker healthy: A review published in June 2018 in The American Journal of Clinical Nutrition suggests that vitamin D supplementation may help lower LDL (bad) cholesterol levels. This is important to note because people with type 2 diabetes are at a greater risk for heart problems. In fact, the Centers for Disease Control and Prevention notes people with diabetes are two times more likely to die from heart disease than people without diabetes. RELATED: The Relationship Between Heart Disease and Type 2 Diabetes
How Are Vitamin D and Diabetes Connected?
A growing number of studies suggest a link between vitamin D and type 2 diabetes. “Studies have found that people who have insulin resistance and a low level of vitamin D may have a higher risk of developing type 2 diabetes,” says Vandana R. Sheth, RDN, CDCES, a spokesperson for the Academy of Nutrition and Dietetics, who is in private practice in Rancho Palos Verdes, California. It’s also been noted that people newly diagnosed with type 2 diabetes tend to have lower vitamin D levels than people without the disease. “In type 2 diabetes, sometimes the cells of the pancreas do not work properly and struggle to produce sufficient insulin to help control blood sugar levels,” explains Shahzadi Devje, RD, CDE, of Toronto, Canada. “Specific receptors in the pancreas may only switch on when sufficient vitamin D is available. The thinking is that vitamin D may support the function of the pancreas.” A small randomized controlled trial published in September 2019 in the European Journal of Endocrinology found vitamin D supplementation for six months improved insulin sensitivity and production in 96 participants at high risk of or newly diagnosed with type 2 diabetes. The findings suggest that vitamin D may help delay type 2 diabetes. Also, vitamin D supplementation may reduce the risk of developing type 2 diabetes in people who have low levels of vitamin D and a high risk of developing the condition, according to a review published in September 2019 in the journal Current Diabetes Reports. Furthermore, getting enough vitamin D may also help reduce insulin resistance, which is the hallmark of type 2 diabetes, found the Current Diabetes Reports review. This may help prevent the onset of type 2 diabetes in the first place. RELATED: 10 Illnesses Linked With Vitamin D Deficiency
What We Don’t Yet Know About the Benefits of Vitamin D for Diabetes
Yet more research is still needed in this area. Importantly, the American Diabetes Association (ADA) notes that there’s insufficient evidence to recommend the routine use of vitamin D to improve blood sugar control in people who have diabetes, and not all research suggests that vitamin D is useful when it comes to preventing diabetes. For example, a study published in June 2019 in The New England Journal of Medicine looked at close to 2,500 people at risk for type 2 diabetes who either received vitamin D supplementation of 4,000 international units (IU) or received a placebo. After two years, the people receiving the supplements did not have a significantly lower risk of diabetes than people receiving the placebo. “It’s important to review the scientific evidence with a critical lens,” says Devje. “Much of the research has focused on observational and epidemiological studies, which illustrate an association between vitamin D and diabetes, and do not prove causality.” RELATED: What Vitamin D Can and Can’t Do for Your Health
What Factors Can Lead to a Vitamin D Deficiency?
Regardless, experts agree getting enough vitamin D is important for overall health, so you should make sure you’re getting your fix. Although the optimal source of vitamin D is sunlight, it can be challenging to get your daily dose this way, especially during the winter months in northern climates. You’d need to be outside during peak daytime hours — typically 10 a.m. to 3 p.m. standard time or 11 a.m. to 4 p.m. daylight saving time — and soak in the rays at least twice a week for 5 to 30 minutes, then stop and apply sunscreen, according to the NIH. The app Dminder tracks the sun to help you get optimal vitamin D. “You may struggle to get enough vitamin D if you don’t get sufficient sunlight, because many of us spend a significant portion of our day indoors,” says Devje. “People who cover their skin all the time with sunscreen or clothes may also struggle to get enough vitamin D from sunlight.” According to the Harvard T.H. Chan School of Public Health, people with darker skin are at a greater risk for insufficiency because the skin acts as a natural sunscreen, slowing production of vitamin D, while people who are overweight or obese also tend to have lower levels of vitamin D. RELATED: A Complete Guide to Vitamin D Deficiency
What Foods Are High in Vitamin D Yet Also Diabetes-Friendly?
Besides sunlight, another great way to take in more vitamin D is from food. According to the NIH, food sources of vitamin D include fatty fish (such as salmon, herring, and tuna), fortified foods (milk, yogurt, orange juice, and some cereals and breads), and eggs, as well as smaller amounts from some cheeses and some kinds of mushrooms. If your blood levels of vitamin D are too low, your doctor may recommend a supplement. To determine if you need one, speak with your doctor about getting your levels tested. “I always recommend my clients with diabetes be screened for a vitamin D deficiency so the appropriate vitamin D supplementation level can be recommended,” says Palinski-Wade. A registered dietitian can help you find vitamin D-rich foods that fit into your diabetes-friendly meal plan. You can find a registered dietitian who is also a certified diabetes care and education specialist in your area using the Academy of Nutrition and Dietetics’ Find an Expert tool. RELATED: COVID D-Prived and Down? How Vitamin D Deficiency Can Contribute to Low Mood
How Much Vitamin D Should People With or at Risk for Diabetes Take?
The daily vitamin D intake goal for most adults is 600 IU, and adults over age 70 need a little more — 800 IU — according to the National Institutes of Health (NIH). People with diabetes are no exception. There are two main forms of vitamin D — vitamin D2 and vitamin D3. Vitamin D2 is found in plants and fortified foods, while vitamin D3 comes from animal sources and is produced naturally in the body when your skin is exposed to sunlight. In terms of supplements, vegans can take vitamin D2, but for optimal benefits, vitamin D3 may be more effective, according to the Harvard T.H. Chan School of Public Health. This may be due in part to differences in their chemical structures and ability to bind to vitamin D receptors, according to a review published in August 2017 in the journal Proceedings of the Nutrition Society. Make sure to choose a supplement that’s been tested by a third party so you know it contains what it says it does on the label. “I suggest opting for drops, emulsions, powders, or capsules to increase chances of absorption,” says Devje. RELATED: Can a Supplement Protect Me From the New Coronavirus?
Can You Take Too Much Vitamin D, and How Do You Know if You Have?
Be careful about taking too high of a supplement dose, as research suggests there’s such a thing as taking too much vitamin D. Consider an article published in June 2017 in the journal JAMA that looked at observational data of more than 39,000 survey participants from the National Health and Nutrition Examination Survey (NHANES). During 2013–2014, 18 percent of the population took in more than 1,000 IU vitamin D daily, and 3 percent took in more than the tolerable upper limit of 4,000 IU daily. Getting too much vitamin D may be linked with heightened risk of fractures and falls in the elderly, and a higher risk of kidney stones when the higher vitamin D intake is alongside calcium. People with diabetes also face risks from going overboard on vitamin D. “Very high doses of vitamin D can lead to toxicity that can cause nausea, vomiting, and other complications,” says Palinksi-Wade. Also, people with type 2 diabetes — who have a higher risk of heart and kidney disease — should be aware that excess vitamin D intake can harden blood vessels and tissue due to raised blood levels of calcium, which can lead to heart and kidney damage, according to the NIH. And vitamin D can interfere with certain medications, so talk to your doctor before starting supplements. If you’re unsure about whether you’re getting enough or too much vitamin D, consult your healthcare provider, who can give you blood tests to test for vitamin D deficiency or excess. Learn more about this vitamin in Diabetes Daily’s article “Vitamin D and Diabetes: What’s the Connection?”
