A study into dietary supplement trends in the United States has identified a link between taking too much of certain vitamins and the increased risk of hip fractures.
The study, reported in the journal JAMA Network Open, found that older women who take high doses of vitamins B-6 and B-12 are more likely to suffer hip fractures than those who do not. Researchers tested over 75,000 women in the United States over several years, and compared those who took more than the recommended dose of vitamins B-6 and B-12 with those who took lower amounts. The former were 47 per cent more likely to suffer a hip fracture during the period of the study. Normal intakes of these vitamins were not associated with any increased risk.
Vitamins B-6 and B-12 have reportedly been linked with a lower risk of heart disease, and moderate doses are generally regarded as essential as part of a healthy, varied diet. Vitamin B-6 helps the body to form haemoglobin, the molecule that carries oxygen in the red blood cells. The vitamin also helps fight infection and maintain normal blood glucose levels. Vitamin B-6 is found in animal products such as beef, poultry and fish, and in plant sources such as avocados. Vitamin B-12 is necessary for the production of DNA, hormones and red blood cells. Cooked beef liver is among the best sources of vitamin B-12, but it can also be found in seafood and dairy products.
The study did not form a conclusion as to whether these vitamins actually increase the risk of hip fracture, or whether there may be other side effects of consuming B-6 and B-12 that also lead to increased fracture risk. For example, very high doses of B-6 are thought to produce neurological symptoms and decreased muscle tone, which may increase the likelihood of falls, rather than weakening the bones, particularly in older people. Equally, it may be that participants in the study who were feeling unwell already, and were therefore more likely to suffer illness or injury, began to take more vitamins.
Sufficient amounts of vitamins B-6 and B-12 can be found naturally in many healthy and varied diets, but if a patient is deficient in one of these vitamins, GPs may advise taking a supplement. The authors of the study have commented that consuming too much of a certain nutrient can be harmful, just as taking too little can be. The results of the study suggest why caution is needed and why primary care providers should be consulted before a patient begins taking supplements.