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TalkingNutrition

Providing perspectives on recent research into vitamins and nutritionals

Dog_wagging_tail

The Tail that Wags the Dog: Identifying People with the Greatest Nutritional Risks

By Michael McBurney

Yesterday I wrote that dietary supplements can be important contributors to nutrient intake and health. Many health professionals reject this premise, fearing it undermines determination to make healthy food choices. Others worry about questionable ingredients being promoted to enhance sexual performance or stimulate metabolism and weight loss. Some fear excessive use of high potency single vitamins.

Three very different scenarios. All 3 are plausible because a standardized definition doesn’t exist for ‘dietary supplements’. Lack of consensus leads to research chaos and consumer confusion. If population means derived from self-reported dietary intake assessments are flawed, can anything be learned from behaviors associated with supplement use?

A cross-sectional survey of 54,948 Danes, 50-64y of age, finds that 71% report using dietary supplements. Users were more likely to be older, more educated, and female but the health benefits of supplement use were confounded by lifestyle and dietary choices (composition). Similar healthy behaviors of supplement users have been reported in the US. They are more likely to report healthier dietary and physical activity behaviors. Using 2007-2010 NHANES data, we defined multivitamin-mineral (MMVM) supplements as those containing ≥9 micronutrients at 100% of the RDA. Fifty-one percent of 16,444 American adults reported using MMVM supplements. Regular/daily users of MVMM products had the highest nutrient intakes.

Measuring the nutrient status of populations from dietary records isn’t very precise. It is true that frequency of away-from-home and fast-food meals is positively associated with BMI and serum concentrations of total, LDL, HDL-cholesterol and negatively associated with serum concentrations of micronutrients (except for lycopene most often consumed in ketchup and vitamin A in beef and chicken!). Yet, a more detailed analysis (see table below) finds few ‘biologically-relevant’ differences in mean serum biomarkers between folks eating 0 versus ≥ 6 meals per week away-from-home.

Serum biomarker

Weekly frequency of away-from-home meals

P value

0

≥6 times

  Vitamin A, µg/dL

59.3

58.3

0.2

  Vitamin D, ng/mL

22

21

0.01

  Vitamin E, µg/dL

1193

1148

0.001

  Vitamin C, µmol/L

56

52

0.008

  Folate, ng/mL

12.5

11.0

0.0001

  Red blood cell folate, ng/mL

285

266

0.007

  Vitamin B12, pg/mL

483

459

0.04

  Pyridoxal-5’-phosphate, nmol/L

52.2

46.5

0.002

  α-carotene, µg/dL

3.43

2.15

0.0001

  Trans-β-carotene, µg/dL

14.2

10.8

0.0001

  Lutein-zeaxanthin, µg/dL

14.9

14.0

0.05

  β-cryptoxanthin, µg/dL

7.85

6.96

0.01

  Total lycopene, µg/dL

37.4

40.3

0.1

There is an expression: a book cannot be judged by its cover. The quality of a library isn’t measured by the average book; it is a reflection of the breadth of its collection. Similarly, population means of self-reported data does not provide a meaningful measure of nutritional status of its individuals.

The nutritional status of the average person isn’t our greatest concern. We should be worried about the people at the tails of the distribution because these are the ones which drive health care costs. We need to identify those who are malnourished or excessively over-nourished.

In the absence of identifying people at greatest health risk by behavior or nutritional status, multivitamin-mineral supplements are a safe, effective means to increase nutritional status. Millions of people seem to understand the value of multivitamin-mineral supplements as a form of insurance. People who are not using dietary supplements could benefit the most.

Main Citations

Kofoed CLF, Christensen J, Dragsted LO, Tjonneland A, Roswall N. Determinants of dietary supplement use – healthy individuals use supplements. 2015 Br J Nutr doi: 10.1017/S0007114515001440

Kant AK, Whitley MI, Graubard BI. Away from home meals: associations with biomarkers of chronic disease and dietary intake in American adults, NHANES 2005-2010. 2015 Int J Obes doi: 10.1038/ijo.2014.183

Other Citations

Dickinson A, Blatman J, El-Dash N, Franco JC. Common usage and reasons for using dietary supplements: Report of a series of surveys. 2014 J Am Coll Nutr doi: 10.1080/07315724.2013.875423

Wallace TC, McBurney M, Fulgoni III VL. Multivitamin/mineral supplement contribution to micronutrient intakes in the United States, 2007-1010. 2014 J Am Coll Nutr doi: 10.1080/07315724.2013.846806


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