Vitamin D deficiency common in sunny southern Arizona

March 25, 2008

Outright Vitamin D deficiency or minimal insufficiency has been observed among populations in the northern United States. However, data on the prevalence of vitamin D deficiency in areas of high sun exposure, such as Arizona, are limited. Interaction between the suns rays and cholesterol in the skin creates Vitamin D and it is thought that sufficient sun exposure results in sufficient plasma levels of Vitamin D.
The serum from participants in a colorectal adenoma prevention study was analyzed to determine rates of vitamin D deficiency. Participants were categorized into 4 groups on the basis of serum 25(OH)D concentrations: less than 10.0 ng/ml, between to 10.0 and 20.0 ng/ml, between 20.0 to 30.0 ng/ml, and greater than or equal to 30.0 ng/ml.
The mean serum 25(OH)D concentration for the total population was 26 ng/ml. Of 637 participants, 22.3% had 25(OH)D concentrations greater than 30 ng/ml, 25.4% had concentrations less than 20 ng/ml, and 2.0% had concentrations less than 10 ng/ml. Blacks (55.5%) and Hispanics (37.6%) were more likely to have deficient 25(OH)D concentrations (less than 20 ng/ml) than were non-Hispanic whites (22.7%). Sun exposure had a greater effect on 25(OH)D in whites than in blacks and Hispanics, whereas body mass index appeared to be more important in the latter groups. Despite residing in a region with high chronic sun exposure, adults in southern Arizona are commonly deficient in vitamin D, particularly blacks and Hispanics. The study is published in the March 2008 issue of The American Journal of Clinical Nutrition.

Alkaline diets favor better muscle mass in older adults

Scientists from the Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston state that it is important for seniors to maintain muscle while to prevent falls and bone fractures. Metabolic acidosis causes muscle loss, and the acid load from diets that are high in acid–producing protein and cereal grains in comparison to the consumption of alkalinizing fruit and vegetables may therefore contribute to a loss of muscle mass in older adults.
The scientist compared 24-h urinary potassium and an index of fruit and vegetable intake with the percentage lean body mass (%LBM) or loss muscle in older subjects - 384 men and women aged 65 or older who participated in a 3-y trial comparing calcium and vitamin D with placebo. Potassium was measured in 24-h urine collections at baseline (meaning right before the start of the study).
At baseline, the mean urinary potassium excretion was 67 mmol/d. There was a connection between higher potassium in the urine and maintaining a healthier muscle mass. Higher intake of foods rich in potassium, such as fruit and vegetables, may favor the preservation of muscle mass in older men and women. The study is published in the March 2008 issue of The American Journal of Clinical Nutrition