Consumption of vitamin B6 and folate protects against CVD in type 2 diabetes patients

The findings, published in Karger's Annals of Nutrition and Metabolism, indicate that dietary vitamin B6 and folate are protective against CVD in patients with type 2 diabetes.

Cardiovascular diseases are the leading cause of death worldwide. A common risk factor for CVD is type 2 diabetes (T2D), and T2D patients are at a 2- to 4-fold higher risk than the general population. Thus, exploring approaches to reduce the CVD risk among T2D patients is imperative.

Previous studies have shown that dietary one-carbon metabolism-related B vitamins, including vitamin B12, vitamin B6, and folate, are linked with a lower risk of CVD in the general population through their effects on homocysteine metabolism. However, studies assessing their associations in type 2 diabetes patients are lacking. Therefore, Shangling Wu, Department of Nutrition, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China, and colleagues aimed to assess the associations between the intake of three one-carbon metabolism-related B-vitamins (vitamin B6, folate, and vitamin B12) and CVD risk in Chinese T2D patients.

For this purpose, the researchers conducted a hospital-based case-control study of 419 T2D patients and newly diagnosed CVD and 419 age- (±5 years) and sex-matched T2D-only controls in China. During face-to-face interviews, dietary B-vitamin intake was measured using a validated 79-item semiquantitative food-frequency questionnaire. The mean age of the cases was 62.1 years, and that of the controls was 62.1 years.

The study led to the following findings:

• No significant differences between cases and controls were observed regarding age, household income, work status in the past year, marital status, smoking status, alcohol consumption, dyslipidemia, and multivitamin supplement use.
• Control subjects' median intakes of folate, vitamin B6, and vitamin B12 were 160.19 µg/day, 0.74 mg/day, and 1.40 µg/day, respectively. The cases had a lower folate and vitamin B6 intake than the controls.
• No significant differences between the cases and controls were observed for vitamin B12 intake.
• Overall, eggs and vegetables, including pakchoi, rape, lettuce, spinach, amaranth, and macaroni, contributed >35.8% of the total folate intake; meat and vegetables were the primary sources of complete vitamin B6, and meat and fish were the primary sources of comprehensive vitamin B12. The five main sources of these nutrients accounted for 49.7% of folate, 50.8% of vitamin B6, and 88.2% of vitamin B12.
• Except for vitamin B12 and folate among cases, the intake of folate, vitamin B6, and vitamin B12 by the cases and controls were all significantly correlated.
• Among T2D patients, high intakes of folate and vitamin B6 were each related to a low risk of CVD. The associations were consistently inverse in univariate and multivariable analyses.
• After adjustment for various potential confounders, the adjusted ORs for the highest quartile of dietary folate and vitamin B6 were found to be 0.32 and 0.47, respectively, compared with those for the lowest quartile. T
• The association for vitamin B12 was not statistically significant, and the adjusted OR comparing the extreme quartiles was 1.02.
• A consistent inverse association was found between folate intake from vegetables, eggs, soy fruits, and other foods and CVD risk but not among folate intake from grains.
• Stratified analyses were further conducted based on sociodemographic factors, lifestyle, and comorbidity status. No significant interactions were observed, and the associations of folate with CVD risk were similar for all strata. These findings remained unchanged when patients using multivitamin supplements, antidiabetic medication, non-lipid-lowering drugs, and non-anti-hypertensive drugs were excluded from sensitivity analyses.

"The study showed that high folate and vitamin B6 intakes, but not vitamin B12, are associated with a low CVD risk in T2D patients," the researchers wrote in their study. "These findings provide preliminary evidence for the feasibility of a dietary program for CVD prevention in type 2 diabetes patients; however, there is a need for confirming such evidence by further studies."

Reference:

The study, "Dietary Folate, Vitamin B6 and Vitamin B12 and Risk of Cardiovascular Diseases among Individuals with Type 2 Diabetes: a Case-Control Study," was published in Annals of Nutrition and Metabolism.DOI: https://doi.org/10.1159/000527529