~Dr. Gabe Mirkin's Fitness and Health e-Zine
This month researchers showed that having low blood levels of hydroxy vitamin D (below 26 mcg/L or 65 nmol/L) increases risk for diabetes (J Nutr, 2014;144(5):734-42). Vitamin D is necessary for insulin to attach to its receptors on cells to drive sugar from the bloodstream into cells. If insulin cannot attach to its receptors, it cannot function, causing blood sugar levels to rise very high.
This was an extremely well done study. They compared many different risk factors for diabetes with blood levels of vitamin D in 239 sedentary, postmenopausal (average age 59.7), overweight women who did not have diabetes. They found that blood levels of hydroxy vitamin D below 26 mcg/L (65 nmol/L) were associated with:
• being overweight,
• storing fat in the belly,
• having a greater percentage of body fat,
• storing fat in the liver,
• being physically unfit (low VO2max),
• having higher blood sugar levels,
• having higher blood insulin levels, and
• having high triglycerides.
Low vitamin D levels were not linked to high blood pressure, high LDL (bad) cholesterol or high total cholesterol.
How Low Levels of Vitamin D can Lead to Diabetes
• Low levels of vitamin D prevent insulin from attaching to its receptors on cells.
• Blood sugar levels rise too high, so the pancreas releases large amounts of insulin.
• Blood insulin levels rise too high. Insulin converts sugar to triglycerides, so
• Blood triglycerides rise too high.
• Triglycerides deposit in the liver to cause a fatty liver. A fatty liver cannot accept sugar from the bloodstream when blood sugar levels are high. (The liver normally lowers high blood sugar levels by accepting sugar from the bloodstream.)
• Blood sugar rises even higher. High blood sugar levels cause sugar to attach to the outer membranes of cells throughout your body and destroy them. This cell destruction causes all of the terrible consequences of diabetes: damage to nerves, kidneys, liver, brain, eyes and other organs, amputations, heart attacks and strokes.
By Gabe Mirkin, M.D.