Supplement use: is there any nutritional benefit?

OBJECTIVE

To examine the role of dietary supplements in improving total nutrient intakes in adults.

DESIGN

Dietitian-administered 24-hour recalls (of intake including supplements) were conducted in 1997 and 1998. Supplement users were categorized into groups based on the types of supplements used and nutrient intake was examined.

SUBJECTS

Using a multistage, stratified random sampling, 1,530 Canadian adults aged 19 to 65 years were surveyed.

STATISTICAL ANALYSES PERFORMED

Intakes from diet, supplements, and diet plus supplements were examined by age/gender stratification.

RESULTS

Supplement users had dietary intakes, from food alone, similar to nonusers with mean intakes in some age/sex groups below the Recommended Daily Allowance (RDA)/Adequate Intake (AI) for iron, calcium, and folate. Multivitamin users had mean intakes (from diet plus supplement) of folate above the RDA and iron intakes also increased to RDA levels among women aged 19 to 50 years. Calcium supplement users had lower calcium and vitamin D intakes than nonusers from diet alone in some age/sex groups. Calcium tablets increased mean calcium intakes to AI levels among all age/sex groups. Many supplement users exceeded the new Upper Limits of safe intake; 47% in the case of niacin.

APPLICATIONS

Supplements are commonly used and can help some persons adhere to Dietary Reference Intake recommendations concerning intake of folate, calcium, vitamin D. and iron. We found multivitamin users to have higher total intakes of folic acid, iron, calcium, and vitamin D. Also, targeted use of calcium supplements effectively enhanced intakes. However, concurrent vitamin D supplementation is important and awareness of product composition with respect to Upper Limits is essential.