People who get plenty of vitamin K from food may have a lower risk of developing type 2 diabetes than those who get less of the vitamin, a new study suggests. Researchers found that among more than 38,000 Dutch adults they followed for a decade, those who got the most vitamin K in their diets were about 20 percent less likely to be diagnosed with type 2 diabetes during the study period. The findings appear to be the first to show a relationship between vitamin K and diabetes risk, and do not prove that the vitamin is the reason for the lower risk, write the researchers, led by Dr. Joline W.J. Beulens of the University Medical Center Utrecht in the Netherlands. Instead, they add, the results should fuel further research into whether vitamin K does play a role in the development of type 2 diabetes. The most important risk factors for type 2 diabetes include older age, obesity, family history of diabetes and race - with black, Hispanic and Native Americans at higher risk than whites in the US. The extent to which specific nutrients in the diet might affect diabetes risk remains unclear. Vitamin K exists in two natural forms: vitamin K1, or phylloquinone, found largely in green leafy vegetables, as well as some vegetable oils, such as canola and soybean oils; and vitamin K2, or menaquinone, which people get mainly through meat, cheese and eggs. In the current study, both vitamins K1 and K2 were related to a lower diabetes risk, but the relationship was stronger with vitamin K2. The findings, reported in the journal Diabetes Care, are based on questionnaires from 38,094 men and women who were between the ages of 20 and 70 at the outset. Participants completed a detailed diet survey, from which each person's average vitamin K intake was estimated; they also answered questions on their overall health and lifestyle habits. Over the next 10 years, 918 study participants were diagnosed with type 2 diabetes, based on their medical records. In general, Beulens and her colleagues found, the risk of developing type 2 diabetes dipped for every 10-microgram (mcg) increase in vitamin K2 intake. Overall, the one-quarter of participants with the highest intake were 20 percent less likely to be diagnosed with diabetes than the one-quarter with the lowest intake. With vitamin K1, no decreased risk was seen until consumption of the vitamin was relatively high. Similar to the findings with vitamin K2, the one-quarter of men and women who got the most vitamin K1 were 19 percent less likely to develop diabetes than the quarter with the lowest intake. The researchers accounted for a number of other factors important in diabetes risk, including age, body weight and exercise habits. They also considered other dietary habits, like total calorie intake and consumption of certain other nutrients, like fat, fiber and vitamins C and E. Still, higher vitamin K intake, itself, was linked to a lower diabetes risk. Exactly why the vitamin might be protective is not known. However, Beulens and her colleagues note, there is evidence that vitamin K reduces systemic inflammation, which may improve the body's use of the blood-sugar-regulating hormone insulin. More research, they say, is needed both to confirm these findings and to study the potential underlying reasons. - ReutersCommon diabetes drug linked to vitamin deficiencyBy Kate Kelland Patients treated over long periods with metformin, a common drug for diabetes, are at risk of developing vitamin B12 deficiency which is also likely to get worse over time, according to a study published last Friday. Dutch scientists who carried out the study said the findings suggest that regular checking of vitamin B-12 levels during long-term metformin treatment should be “strongly considered” to try to prevent deficiency and its effects. Vitamin B12 is essential to maintain healthy nerve cells and red blood cells. It is found in meat, dairy products, eggs, fish, shellfish and fortified breakfast cereals, and it also can be taken as a supplement. Coen Stehouwer of Maastricht University Medical Centre in the Netherlands, whose study was published in the British Medical Journal, said symptoms of B12 deficiency include fatigue, mental changes, anaemia and nerve damage known as neuropathy. All these symptoms can easily be misdiagnosed as being due to diabetes and its complications, or to ageing, he said, but checking B12 levels could help doctors to assess the real cause and treat it if it was found to be B12 deficiency. Stehouwer's team studied 390 patients with type 2 diabetes, giving metformin to 196 of them three times a day for more than four years, and a placebo, or dummy pill, to the other 194. They found that people who had taken the metformin had a 19 percent reduction in their vitamin B12 levels compared with people who had taken a placebo, who had almost no B12 change. The reduced levels of vitamin B12 in the metformin group also persisted and became more apparent over time, they said.
