Vitamin D and Diabetes

By Charlyn Fargo

January 25, 2019 7 min read

Vitamin D may play a significant role in helping people with prediabetes not develop the disease. In a new study published in Diabetes Care, high-risk patients with the highest blood levels of vitamin D were 28 percent less likely to develop Type 2 diabetes than those with the lowest levels.

Researchers at Tufts University led by Dr. Anastassios Pittas, an associate professor at Tufts School of Medicine, studied 2,039 participants in the Diabetes Prevention Program, a multicenter trial of strategies to prevent diabetes in people with prediabetes. Blood levels of vitamin D were tested multiple times over an average 2.7 years. After adjusting for other diabetes risk factors, those in the top third of vitamin D status were significantly less likely to progress to diabetes.

How does it work? Vitamin D could help ward off diabetes by improving the workings of the pancreas, which plays a key role in the disease. In a 2011 randomized trial published in the American Journal of Clinical Nutrition, Tufts researchers found that daily supplementation of vitamin D boosted the function of cells in the pancreas that produce insulin. The study of 92 overweight adults with prediabetes tested supplementation with 2,000 IU of vitamin D daily versus a placebo. After 20 weeks, those taking vitamin D saw a 26 percent improvement in functioning of cells in the pancreas, while those in the control group experienced a 14 percent decline.

There seems to be a strong link between more vitamin D and less risk for diabetes. The bottom line? Have your doctor do a blood test to determine your vitamin D level. For most people over 50, a supplement may be needed. It's true that our bodies can make vitamin D from the sun, but if you wear sunscreen or dress in layers, especially in the winter, your body won't be making enough vitamin D.

Keep in mind vitamin D is a fat-soluble vitamin, so it's best absorbed with food, particularly food with fat. If you take your supplement in the morning, take it with cream in your coffee.

Q and A

Q: I am a vegetarian. Is it necessary for me to eat certain foods together in order to ensure I get appropriate protein?

A: It is not necessary to eat certain foods together in one meal in order to meet protein needs on a vegetarian diet. According to the 2009 American Dietetic Association Position Paper on Vegetarian Diets, as long as one is eating a varied diet and meeting energy needs, there is no need to worry about the timing of when foods are consumed. In order to build proteins in our bodies, we need to get nine essential amino acids from the foods we eat. The idea of complementary foods comes from the finding that not all protein sources supply sufficient levels of all nine essential amino acids. As an example, beans have low levels of methionine but high levels of lysine; rice has less lysine but plenty of methionine. Eating those together supplies adequate level of both amino acids. But eating them (or other foods) separately does, too. Because metabolism is a dynamic process, with things being broken down and built up constantly, we now understand that strict protein combining at each meal is not necessary. As long as one eats a variety of foods throughout the day, there is no need to worry about eating particular combinations of foods.

Information courtesy of Tufts University Health & Nutrition Letter.


Buddha bowls are an easy make-ahead-of-time healthy lunch to pack and take with you to work or school. Here's a recipe from Hy-Vee for lemon chicken quinoa bowls. Set aside time on a Sunday afternoon to make them so you're ready for the week. You can mix and match vegetables as you like.


1 pound boneless, skinless chicken breasts

1 tablespoon lemon zest, divided

1/2 cup fresh lemon juice, divided

2/3 cup olive oil, divided

2 tablespoons fresh oregano, chopped

1/2 teaspoon lemon pepper seasoning, divided

2 teaspoons honey

1 cup dry tricolor quinoa

2 cups lower-sodium chicken broth

Nonstick cooking spray

2 cups broccoli florets

6 cups lightly packed arugula

2 cups halved red and/or yellow cherry tomatoes

1/2 cucumber (seedless), thinly sliced

Chopped fresh lemon, for garnish

Crumbled feta cheese, for garnish

Lightly pound chicken to an even thickness. Place chicken in a large resealable plastic bag. Combine 2 teaspoons lemon zest, 1/4 cup lemon juice, 1/3 cup olive oil, oregano and 1/4 teaspoon lemon pepper seasoning in a small bowl. Pour marinade over chicken; seal bag. Turn bag to coat chicken with marinade. Marinate in the refrigerator for 30 to 60 minutes. Whisk together remaining 1/3 cup olive oil, remaining 1/4 cup lemon juice, honey and remaining 1/4 teaspoon lemon pepper seasoning in a small bowl. Set aside for vinaigrette.

Place quinoa in a fine mesh sieve. Rinse under cold running water; drain well. Transfer quinoa to a small saucepan; add broth. Bring to boiling; reduce heat. Simmer, covered, for 15 to 20 minutes or until broth is absorbed. Remove from heat. Let stand 5 minutes. Add remaining 1 teaspoon lemon zest and fluff quinoa with a fork. Cover and keep warm.

Drain chicken; discard marinade. Lightly spray a large cast-iron grill pan with cooking spray. Heat over medium heat. Add chicken; cook for 12 to 15 minutes or until done (165 F), turning once. Transfer chicken to a cutting board. Loosely cover with foil and let rest 5 minutes. Cut chicken into 1/2-inch slices. Place broccoli in a microwave-safe bowl. Add 1 to 2 tablespoons water. Microwave, covered on high for 3 to 5 minutes or until crisp-tender. Divide arugula among four serving bowls. Arrange chicken slices, quinoa, broccoli, tomatoes and cucumber on top. Garnish with chopped lemon and crumbled feta cheese. Drizzle with vinaigrette. Sprinkle with additional lemon pepper, if desired. Serves 4.

Per serving: 670 calories; 35 grams protein; 40 grams carbohydrates; 42 grams fat; (6 grams saturated; 0 grams trans fats); 85 milligrams cholesterol; 6 grams fiber; 9 grams sugar (3 grams added); 390 milligrams sodium.

Charlyn Fargo is a registered dietitian at Hy-Vee in Springfield, Illinois, and the media representative for the Illinois Academy of Nutrition and Dietetics. For comments or questions, contact her at [email protected] or follow her on Twitter @NutritionRD. To find out more about Charlyn Fargo and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at

Photo credit: at Pixabay

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