New Iowa State research holds promise for diabetics with vitamin D deficiency


Vitamin D is important for bone health and protecting against cancer and other diseases, but diabetics have trouble retaining it and other nutrients because of poor kidney function. A team of Iowa State researchers found diabetic rats fed an egg-based diet had higher concentrations of vitamin D, improved blood glucose levels and gained less weight.

Iowa State researchers are most interested in 25-hydroxyvitamin D-3 (25D) — the form of vitamin D in the blood that reflects vitamin D status. For that reason, it made sense to test eggs in the diet rather than other foods containing vitamin D or a supplement.

"Eggs are the richest source of 25-hydroxyvitamin D-3 in the diet, and there isn't any conversion required to make it into the blood. If you take it in a supplement or food fortified with vitamin D, it has to be converted to that form," said Matthew Rowling, an associate professor of food science and human nutrition.

The variation in results was significant. Blood glucose levels dropped nearly 50 percent for diabetic rats on an egg-based diet compared to diabetic rats fed a standard diet. Concentrations of 25D were 148 percent higher for the egg-fed group and plasma triglyceride concentrations — a risk factor for cardiovascular disease — dropped 52 percent.


Don't skip the yolk

Eggs are not only a good source of vitamin D and other nutrients; they are also inexpensive and readily available. However, researchers say you need to eat the whole egg.

"If you just ate egg whites you wouldn't get any of the vitamin D, because the 25D is only in the yolk. The whites are fine if you're focused just on protein, but the nutrients are all in the yolk. From a vitamin D standpoint, you want to consume the whole thing," said Jones, lead author of the paper.


"You may need even less egg if you combine it with something else that does not provide vitamin D per se, but rather protects the kidney and prevents loss of vitamin D," Schalinske said. "We want to make sure we understand what's going on with egg consumption and promoting vitamin D balance and make sure there's a linkage to outcomes whether it's bone health or kidney health."


Gar Yee Koh, a postdoctoral research associate at Tufts University, also contributed to this paper. The research was funded by the Egg Nutrition Center.

Media Contact

Kevin Schalinske
[email protected]

%d bloggers like this: