Diet & Fitness

Vitamin K is needed for bone formation. People with osteoporosis have been reported to have low blood levels^2,3 and low dietary intake of vitamin K.^4,5 One study found that postmenopausal (though not premenopausal) women may reduce urinary loss of calcium by taking 1 mg of vitamin K1 per day.⁶ People with osteoporosis given large amounts of vitamin K2 in the form of menaquinine-4 (45 mg per day) have shown an increase in bone density after six months⁷ and decreased bone loss after one⁸ or two⁹ years. Supplementation with vitamin K2 in the form of menaquinone-7 (180-375 mcg per day) has been reported to improve bone quality and to slow both bone loss and the loss of vertebral height in postmenopausal women.^10,11

In a double-blind trial, supplementing with vitamin K1 for three years appeared to slow the rate of progression of coronary artery calcification in elderly people who had preexisting coronary artery calcification. Participants in that study were randomly assigned to receive a multivitamin that contained 500 mcg per day of vitamin K1 or the same multivitamin without vitamin K1.¹²

 

The malabsorption that occurs in celiac disease can lead to multiple nutritional deficiencies. The most common nutritional problems in people with celiac disease include deficiencies of essential fatty acids, iron, vitamin D, vitamin K, calcium, magnesium, and folic acid.¹³Zinc malabsorption also occurs frequently in celiac disease¹⁴ and may result in zinc deficiency, even in people who are otherwise in remission.¹⁵ People with newly diagnosed celiac disease should be assessed for nutritional deficiencies by a doctor. Celiac patients who have not yet completely recovered should supplement with a high-potency multivitamin-mineral. Some patients may require even higher amounts of some of these vitamins and minerals—an issue that should be discussed with their healthcare practitioner. Evidence of a nutrient deficiency in a celiac patient is a clear indication for supplementation with that nutrient.

After commencement of a gluten-free diet, overall nutritional status gradually improves. However, deficiencies of some nutrients may persist, even in people who are strictly avoiding gluten. For example, magnesium deficiency was found in 8 of 23 adults with celiac disease who had been following a gluten-free diet and were symptom-free. When these adults were supplemented with magnesium for two years, their bone mineral density increased significantly.¹⁶

 

In people with Crohn's disease, vitamin K deficiency can result from malabsorption due to intestinal inflammation or bowel surgery, from chronic diarrhea, or from dietary changes necessitated by food intolerance. In addition, Crohn's disease is often treated with antibiotics that have the potential to kill beneficial vitamin K–producing bacteria in the intestines. Vitamin K levels were significantly lower in a group of people with Crohn's disease than in healthy people. Moreover, the rate of bone loss in the Crohn's disease patients increased with increasing degrees of vitamin K deficiency.¹⁷ When combined with earlier evidence that vitamin K is required to maintain healthy bones, this study suggests that vitamin K deficiency is a contributing factor to the accelerated bone loss that often occurs in people with Crohn's disease.

 

Vitamin K and vitamin C, taken together, may provide relief of symptoms for some women. In one study, 91% of women who took 5 mg of vitamin K and 25 mg of vitamin C per day reported the complete disappearance of morning sickness within three days.¹⁸ Menadione was removed from the market a number of years ago because of concerns about potential toxicity. Although some doctors still use a combination of vitamin K1 (the most prevalent form of vitamin K in food) and vitamin C for morning sickness, no studies on this treatment have been done.