Vitamin K may help older men avoid insulin resistance

Resisting Resistance

You may never think about insulin. But if you’re overweight or if you’ve passed your 45th birthday, there’s no escaping the harsh reality: The way your body uses insulin is a HUGE factor in your overall health.

It’s actually pretty simple.

Insulin manages blood sugar by allowing its passage into cells where it’s used for energy or stored in muscles or the liver for later use. But over time, the amount of insulin supplied by the pancreas may not be enough to properly manage blood sugar. The result: insulin resistance. Excess sugar builds up in the blood prompting type 2 diabetes and a cascade of daunting health risks.

For most of us, avoiding insulin resistance is simple. Not easy, but simple. You do two things: 1) you exercise, and 2) you curb your diet to avoid sugar and simple carbohydrates (especially from highly processed foods).

Then, for some, a high intake of a single vitamin may significantly help your efforts.

Mars and Venus

In a previous animal study, researchers found that vitamin K played a role in regulating insulin in mice. So researchers at the Jean Mayer USDA Human Nutrition Research Center at Tufts University designed a trial to test the effect of vitamin K on insulin sensitivity in humans.

STUDY PROFILE

More than 350 non-diabetic men and women over the age of 60 were recruited
Subjects were divided into two groups to receive either 500 micrograms of vitamin K1 daily, or a placebo
The intervention period lasted three years
Results showed a significantly lower measurement for insulin resistance among men in the K1 group compared to placebo
Researchers couldn’t explain why this difference wasn’t seen among female subjects

In the journal Diabetes Care, the authors note that 500 micrograms per day is a dose that’s attainable by diet. It also happens to be considerably higher than the current vitamin K RDA, which is 80 micrograms for men, and 70 women.

Alternative health care pioneer Jonathan V. Wright, M.D., has long recommended vitamin K supplements for those with a family history of osteoporosis or arteriosclerosis (narrowing of the arteries). Dr. Wright suggests 5 to 15 milligrams (not micrograms) of vitamin K per day.

He adds that vitamin K is fat-soluble, so absorption of the vitamin will be maximized if it’s taken with at least a small amount of fat. [Jen: Please use this link to Dr. Wright’s highlighted name above: http://wrightnewsletter.com/healthy/newsletter.html ]

Take 2, avoid 3

Almost all dietary intake of vitamin K comes in the form of K1, which is mostly found in dark, leafy green vegetables, broccoli, asparagus, tomatoes, avocados, olive oil, whole wheat, butter, and green tea. Vitamin K1 is converted into K2 in the intestine, but we get some amount of K2 directly from meat, liver, egg yolk, and fermented products such as yogurt and cheese.

When choosing a vitamin K supplement, be aware of the three different forms: K1, K2, and K3. The latter is a synthetic form and is best avoided. According to HSI Panelist Allan Spreen, M.D., K3 may be responsible for liver toxicity and anemia when taken in high doses.

Before supplementing with vitamin K, talk to your doctor about this important vitamin which may interfere with coumadin, a blood thinner.

Source:
“Effect of Vitamin K Supplementation on Insulin Resistance in Older Men and Women” Diabetes Care, published online ahead of print, 8/12/08, care.diabetesjournals.org