Effects of vitamin D supplementation on 25-hydroxyvitamin D, high-density lipoprotein cholesterol, and other cardiovascular disease risk markers in subjects with elevated waist circumference.

The objective of the present trial was to assess the effects of vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D] and high-density lipoprotein cholesterol (HDL-C) in subjects with high waist circumference. Subjects were randomly assigned a daily multivitamin and mineral (MVM) supplement or a MVM supplement plus vitamin D 1,200 IU/day (MVM+D) for 8 weeks. There was a significant difference in mean change for 25(OH)D between the MVM and MVM+D treatment groups ( - 1.2 ± 2.5 nmol/l vs. 11.7 ± 3.0 nmol/l, respectively; P = 0.003). Vitamin D 1,200 IU/day did not increase 25(OH)D to a desirable level ( ≥ 75 nmol/l) in 61% of participants. There were no significant changes in cardiovascular disease risk markers. Thus, vitamin D supplementation with 1,200 IU/day was insufficient to achieve desirable serum 25(OH)D in most participants and did not affect cardiovascular disease risk markers.

Serum 25-hydroxyvitamin D is independently associated with high-density lipoprotein cholesterol and the metabolic syndrome in men and women.

BACKGROUND: Low vitamin D status has been associated with markers of cardiovascular disease risk. OBJECTIVE: This cross-sectional study assessed the relationships between serum 25-hydroxyvitamin D [25(OH)D] and selected markers for cardiovascular disease risk, including metabolic syndrome and its components, in adult men and women. METHODS: Fasting blood samples, anthropometric measurements, and blood pressure were assessed in 257 men and women. Dietary intake was assessed with food frequency and dietary supplement questionnaires. RESULTS: Total vitamin D intake and that from dietary supplements were significantly associated with increasing serum 25(OH)D tertile (both P < .001). Mean±SEM serum high-density lipoprotein cholesterol (HDL-C) increased in a graded fashion (P < .001) from the lowest (48.4±1.8mg/dL) to the highest (62.3±2.1mg/dL) 25(OH)D tertile. The relationship between 25(OH)D and HDL-C remained significant (P < .001) after adjustment for established determinants of the HDL-C, with each 10-ng/mL increase in 25(OH)D associated with a 4.2-mg/dL increase in HDL-C concentration. Serum triglycerides (P=.008), waist circumference (P < .001), and body mass index (P < .001) showed graded, inverse relationships with 25(OH)D tertile, and the prevalence of metabolic syndrome decreased significantly from the lowest to the highest 25(OH)D tertile (31%, 14%, and 10%, respectively, P for trend=.001). CONCLUSIONS: Lower serum 25(OH)D is associated with the metabolic syndrome and adverse values for some metabolic syndrome risk factors, particularly the HDL-C concentration. Research is warranted to assess whether increasing vitamin D intake will improve the metabolic cardiovascular risk factor profile.

Usage patterns, health, and nutritional status of long-term multiple dietary supplement users: a cross-sectional study.

BACKGROUND: Dietary supplement use in the United States is prevalent and represents an important source of nutrition. However, little is known about individuals who routinely consume multiple dietary supplements. This study describes the dietary supplement usage patterns, health, and nutritional status of long-term multiple dietary supplement users, and where possible makes comparisons to non-users and multivitamin/mineral supplement users. METHODS: Using a cross-sectional study design, information was obtained by online questionnaires and physical examination (fasting blood, blood pressure, body weight) from a convenience sample of long-term users of multiple dietary supplements manufactured by Shaklee Corporation (Multiple Supp users, n = 278). Data for non-users (No Supp users, n = 602) and multivitamin/mineral supplement users (Single Supp users, n = 176) were obtained from the National Health and Nutrition Examination Survey (NHANES) 2001-2002 and NHANES III 1988-1994. Logistic regression methods were used to estimate odds ratios with 95% confidence intervals. RESULTS: Dietary supplements consumed on a daily basis by more than 50% of Multiple Supp users included a multivitamin/mineral, B-complex, vitamin C, carotenoids, vitamin E, calcium with vitamin D, omega-3 fatty acids, flavonoids, lecithin, alfalfa, coenzyme Q10 with resveratrol, glucosamine, and a herbal immune supplement. The majority of women also consumed gamma linolenic acid and a probiotic supplement, whereas men also consumed zinc, garlic, saw palmetto, and a soy protein supplement. Serum nutrient concentrations generally increased with increasing dietary supplement use. After adjustment for age, gender, income, education and body mass index, greater degree of supplement use was associated with more favorable concentrations of serum homocysteine, C-reactive protein, high-density lipoprotein cholesterol, and triglycerides, as well as lower risk of prevalent elevated blood pressure and diabetes. CONCLUSION: This group of long-term multiple dietary supplement users consumed a broad array of vitamin/mineral, herbal, and condition-specific dietary supplements on a daily basis. They were more likely to have optimal concentrations of chronic disease-related biomarkers, and less likely to have suboptimal blood nutrient concentrations, elevated blood pressure, and diabetes compared to non-users and multivitamin/mineral users. These findings should be confirmed by studying the dietary supplement usage patterns, health, and nutritional status of other groups of heavy users of dietary supplements.