Analytical ingredient content and variability of adult multivitamin/mineral products: national estimates for the Dietary Supplement Ingredient Database

BACKGROUND

Multivitamin/mineral products (MVMs) are the dietary supplements most commonly used by US adults. During manufacturing, some ingredients are added in amounts exceeding the label claims to compensate for expected losses during the shelf life. Establishing the health benefits and harms of MVMs requires accurate estimates of nutrient intake from MVMs based on measures of actual rather than labeled ingredient amounts.

OBJECTIVES

Our goals were to determine relations between analytically measured and labeled ingredient content and to compare adult MVM composition with Recommended Dietary Allowances (RDAs) and Tolerable Upper Intake Levels.

DESIGN

Adult MVMs were purchased while following a national sampling plan and chemically analyzed for vitamin and mineral content with certified reference materials in qualified laboratories. For each ingredient, predicted mean percentage differences between analytically obtained and labeled amounts were calculated with the use of regression equations.

RESULTS

For 12 of 18 nutrients, most products had labeled amounts at or above RDAs. The mean measured content of all ingredients (except thiamin) exceeded labeled amounts (overages). Predicted mean percentage differences exceeded labeled amounts by 1.5-13% for copper, manganese, magnesium, niacin, phosphorus, potassium, folic acid, riboflavin, and vitamins B-12, C, and E, and by ∼25% for selenium and iodine, regardless of labeled amount. In contrast, thiamin, vitamin B-6, calcium, iron, and zinc had linear or quadratic relations between the labeled and percentage differences, with ranges from -6.5% to 8.6%, -3.5% to 21%, 7.1% to 29.3%, -0.5% to 16.4%, and -1.9% to 8.1%, respectively. Analytically adjusted ingredient amounts are linked to adult MVMs reported in the NHANES 2003-2008 via the Dietary Supplement Ingredient Database (http://dsid.usda.nih.gov) to facilitate more accurate intake quantification.

CONCLUSIONS

Vitamin and mineral overages were measured in adult MVMs, most of which already meet RDAs. Therefore, nutrient overexposures from supplements combined with typical food intake may have unintended health consequences, although this would require further examination.

Optimizing Adult Protein Intake During Catabolic Health Conditions

The DRIs define a range of acceptable dietary intakes for each nutrient. The range is defined from the minimum intake to avoid risk of inadequacy (i.e., the RDA) up to an upper limit (UL) based on a detectable risk of adverse effects. For most nutrients, the minimum RDA is based on alleviating a clear deficiency condition, whereas higher intakes are often recommended to optimize specific health outcomes. Evidence is accumulating that similar logic should be applied to dietary recommendations for protein. Although the RDA for protein of 0.8 g/kg body weight is adequate to avoid obvious inadequacies, multiple studies provide evidence that many adults may benefit from protein quantity, quality, and distribution beyond guidelines currently defined by the RDA. Further, the dietary requirement for protein is a surrogate for the constituent amino acids and, in particular, the 9 considered to be indispensable. Leucine provides an important example of an essential amino acid where the RDA of 42 mg/kg body weight is significantly less than the 100-110 mg/kg required to optimize metabolic regulation and skeletal muscle protein synthesis. This review will highlight the benefits of higher protein diets to optimize health during aging, inactivity, bed rest, or metabolic dysfunction such as type 2 diabetes.

Food choice and meal consumption pattern among undergraduate students in two universities in Southwestern Nigeria

The food choices and meal consumption patterns of undergraduate students from two Nigerian universities, Obafemi Awolowo University, Ile-Ife (OAU) and Adekunle Ajasin University, Akungba Akoko (AAU) (n = 402; 199 male and 203 female; overall mean age 23) were studied. The result indicated that 60% of the students (58% male and 62% female) consumed the recommended minimum number of servings of cereal, 50% of the males and 35% of the females in the carbohydrate category while 35% of the males and 42% of the females consumed enough from the meat group. More female students (40%) consumed adequate quantities of fruits and vegetables than their male counterparts (20%) while the consumption of milk and milk substitutes was low (10% male and 25% female). Most students ate twice a day substituting snacks for the third meal. More female students (48%) exceeded their energy requirement than their male counterparts (28%) while 60%, 85% and 40% did not meet the recommended dietary allowance (RDA) for protein, calcium and iron respectively. Body Mass Index (BMI) classification indicated that 29% of the students were overweight, 6% were obese while 13% of the male students were underweight. The unhealthy eating habits of Nigerian university students seemed to be a reflection of poor funding.

Impact of Meeting Different Guidelines for Protein Intake on Muscle Mass and Physical Function in Physically Active Older Women

The role of dietary protein intake on muscle mass and physical function in older adults is important for the prevention of age-related physical limitations. The aim of the present study was to elucidate links between dietary protein intake and muscle mass and physical function in older women meeting current guidelines of objectively assessed physical activity. In 106 women (65 to 70 years old), protein intake was assessed using a 6-day food record and participants were classified into high and low protein intake groups using two Recommended Dietary Allowance (RDA) thresholds (0.8 g·kg⁻¹ bodyweight (BW) and 1.1 g·kg⁻¹ BW). Body composition, aerobic fitness, and quadriceps strength were determined using standardized procedures, and self-reported physical function was assessed using the SF-12 Health Survey. Physical activity was assessed by accelerometry and self-report. Women below the 0.8 g·kg⁻¹ BW threshold had a lower muscle mass (p < 0.05) with no differences in physical function variables. When based on the higher RDA threshold (1.1 g·kg⁻¹ BW), in addition to significant differences in muscle mass, women below the higher threshold had a significantly (p < 0.05) higher likelihood of having physical limitations. In conclusion, the present study supports the RDA threshold of 0.8 g·kg⁻¹ BW of proteins to prevent the loss of muscle mass and emphasizes the importance of the higher RDA threshold of at least 1.1 g·kg⁻¹ BW to infer additional benefits on constructs of physical function. Our study also supports the role of protein intake for healthy ageing, even in older adults meeting guidelines for physical activity.