METFORMIN TREATMENT MAY POSE THE RISK FOR VITAMIN B12 DEFICIENCY AND INCREASED HOMOCYSTEINE LEVELS IN TYPE 2 DIABETIC PATIENTS

Metformin is an increasingly popular therapy for treatment of Type 2 diabetes because of its effectiveness and excellent safety profile.  This observational cohort study compared patients exposed to metformin for more than one year to a non-exposed control group in order to assess Vitamin B12 status during long-term metformin treatment.  Results showed significant correlations between metformin treatment and lower serum cobalamin. Additionally, lower serum cobalamin was associated with higher homocysteine levels. The reason for the metformin-associated vitamin B12 deficiency remains unknown, though this study reinforces the necessity of evaluating vitamin B12 status during metformin treatment and investigating dietary strategies to counter this side effect.

Citation:
Vitamin B12 status of patients treated with metformin: a cross-sectional cohort study. Hermann LS, Nilsson B, Wettre S. The British Journal of Diabetes and Vascular Disease 2004; 4(6):401-406.

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CHOLINE MAY IMPACT HEART DISEASE THROUGH ITS ROLE IN THE METABOLISM OF HOMOCYSTEINE

Many studies have shown the relationship between increased total plasma homocysteine concentration and the increased risk of atherosclerotic vascular disease.  High homocysteine levels can be caused by insufficient methylation of homocysteine to form methionine.  Increased intake of folate, vitamin B12 and vitamin B6 have been shown to help metabalize and, therefore, lower homocysteine levels.  This study examined the role of choline deficiency in homocysteine methylation.  Both mice and men were fed choline-sufficient and choline-deficient diets for 3 weeks and 10 days respectively, followed by a methionine load.  Two hours after the methionine load, choline-deficient mice had twice the homocysteine levels of the choline-fed mice, while the choline-deficient men had 35 % higher homocysteine levels four hours after the methionine load. The methionine-load test is a useful instrument for detecting choline deficiency. The authors suggest that, among its other health benefits, choline may be beneficial in lowering plasma homocysteine even when dietary consumption of folate and other B vitamins is adequate. 

Citation:
Choline deficiency in mice and humans is associated with increased plasma homocysteine concentration after a methionine load. da Costa, KA, Gaffney CE, Fischer LM, Zeisel SH. The American Journal of Clinical Nutrition 2005 Feb;81(2):440-4.

To read the abstract, go to
Choline deficiency in mice and humans is associated with increased plasma homocysteine concentration after a methionine load.

FOLIC ACID AND VITAMIN B12 CAN REDUCE THE RISK OF HIP FRACTURE IN STROKE PATIENTS

Of all osteoporosis-related fractures, hip fractures account for the most deaths, disabilities and medical costs. Stroke patients are two to four times more likely to suffer hip fractures than age-matched healthy control patients.  This study, from the Mitate Hospital in Tagawa, Japan, investigated the occurrence of hip fractures in stroke patients given daily oral treatments of folate and vitamin B12 supplements against those given a double placebo. Before treatment, patients in both groups had high levels of plasma homocysteine and low levels of serum cobalamin and serum folate.  Two years after treatment, the homocysteine levels in the placebo group had increased by 31% while homocysteine levels in the treatment group decreased by 38%.  Coincidentally, the number of hip fractures per 1000 patient-years was 10 in the treatment group and 43 in the placebo group.  The incidence of falls in both groups was similar. The authors suggest that the high occurrence of hip fractures in elderly stroke patients is due to falls and osteoporosis.  The combined treatment with folate and vitamin B12 to lower homocysteine levels can be effective in reducing the risk of hip fractures in elderly patients of both sexes following stroke.

Citation:
Effect of folate and mecobalamin on hip fractures in patients with stroke. Sato Y, Honda Y, Iwamoto J, Kanoko T, Satoh K. The Journal of the American Medical Association 2005; Mar 2;293(9):1082-8.

To read the abstract, go to Effect of folate and mecobalamin on hip fractures in patients with stroke.

Globally, iron deficiency anemia and zinc deficiency are common nutritional challenges affecting more than 1 billion individuals.  A plant-food diet high in phytates, other polyphenols, and dietary fiber has been identified as a primary inhibitor to iron and zinc absorption.  Marginal deficiencies in both minerals can result in serious physical and mental disabilities.  Efforts are being made in different parts of the world to increase the intake of iron and zinc through various dietary strategies.  Milk and other animal food products have been used because both have been shown to enhance zinc and iron absorption.  A recent study showed that the addition of 50g and 75g of meat to a phytate-rich diet increased iron abosorption 44% and 57% respectively.  Since some studies suggest the calcium in dairy products reduces iron absorption, the role of milk is controversial.  This study found that zinc absorption increased significantly with milk and yogurt supplementation while iron absorption was unaffected.

Citation:
The Addition of milk or yogurt to a plant-based diet increases zinc bioavailability but does not affect iron bioavailability in women. Rosado JL, Diaz M, González K, Griffin I, Abrams SA, Preciado R.  The Journal of Nutrition 2005 Mar;135(3):465-8.

To read the abstract, go to
The addition of milk or yogurt to a plant-based diet increases zinc bioavailability but does not affect iron bioavailability in women.

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