The research was published this month in the International Journal for Vitamin and Nutrition Research. It was conducted by two experts from the Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University in Boston. The researchers noted that questions persist about the effectiveness of supplements, as do disagreements about the best way to answer those questions, especially on a population wide scale.
“Despite this widespread acceptance of supplements on the part of the public and health care providers, questions about both the safety and effectiveness of dietary supplements continue to be raised. The gold standard for determining the safety and efficacy of a new pharmaceutical agent is the double-blind, placebo-controlled, randomized clinical trial (RCT), and there has been a movement to hold supplements to the same standard, but this is exceedingly difficult to do for a number of reasons. Observational studies are an alternative to RCTs for considering the question of supplement safety and efficacy, although these studies can be plagued by many issues related to confounding by other healthy lifestyle behaviors associated with supplement use and measurement of usual supplement use,” the authors wrote.
Research took advantage of unique data set of MLM distributors
The research follows on earlier research conducted using data from the 2007–2010 National Health and Examination Survey (NHANES) that found that participants who used multiple dietary supplements in a day had better cardiometabolic health profiles than did the general population. The five most popular supplements observed in that data set were multivitamin/mineral supplements, calcium, omega-3s or fish oil, botanical supplements and vitamin C. Multiple dietary supplement use was defined as using at least two supplements a day. The NHANES data, which was used for comparison, also looked at groups that took only a multivitamin once daily or took another ‘single purpose’ supplement, as well as those who used no supplements at all.
Another study, published in 2007, took a cross sectional snapshot of 287 long term multiple dietary supplement (LTMDS) users who were Shaklee Corporation distributors. By the time that data had been gathered the participants had been LTMDS users for as much as 20 years. The present study looked at data from 235 members of that same group another 10 years further on. After issues with incomplete compliance with lab tests and a few other exclusions the researchers were left with a sample of 156 LTMDS users with at least a 30-year history.
Most metabolic benefits persisted
The outcomes included total cholesterol (plasma), HDL cholesterol (plasma) and LDL cholesterol (calculated), triglycerides (plasma), glucose (serum for LTMDS and plasma for NHANES), insulin (serum), and high sensitivity CRP (plasma), and the prevalence of elevated hemoglobin A1c (HbA1c) and diabetes. To measure these, blood samples were taken from most of the 156 subjects while they were attending a Shaklee national convention held in Cleveland while the balance had their blood samples drawn during home visits.
The findings bore out earlier research that found LTMDS users derived significant benefit from the practice, including benefits on LDL cholesterol levels and measures of fasting glucose. The researchers found that most but not all of the benefits observed earlier persisted after another 10 years.
“Our findings suggest that dietary supplement use, particularly use of MDS, may provide cardiometabolic benefit, consistent with the earlier observations in the LTMDS cohort. Our findings also support evidence from earlier observational studies on dietary supplement use and cardiometabolic risk, although it is beyond the scope of this paper to compare our present findings against all of the evidence for and against a role of dietary supplement use in cardiometabolic risk,” the authors concluded.
AHPA exec cautions again over enthusiasm about findings
Holly Johnson, PhD, chief science officer of the American Herbal Products Association, said the finding is welcome, but must be taken with the usual grains of salt about observational studies in general and population subsets in particular. Does LTMDS use appear effective mostly because the people who make this choice also engage in other healthy habits? What’s the role of the mindset of someone who could maintain the energy and positive outlook necessary to operate a multilevel marketing organization distributorship for 30 years or more?
“This observational study is interesting as it looks at cardiometabolic biomarkers in a unique study population of humans that have used multiple yet undefined dietary supplements for over 30 years, compared to groups that used supplements less frequently or not at all. While the RCT remains the gold standard clinical design for pharmaceuticals, the authors identify challenges with using the RCT approach to study the long term role of herbs and dietary supplements in disease prevention,” Johnson told NutraIngredients-USA.
“The authors however acknowledge significant limitations to observational study design, including in this case that the long term multiple supplement user groups did indeed differ in many aspects from the general US population such as race, ethnicity, income, education, smoking, and dietary supplement use. There may be many factors other than supplement use that could lead to better biomarker levels in the study group including socioeconomic, health, diet, exercise, and lifestyle differences between those who use and do not use dietary supplements. So while these data are interesting, evidence from observational studies alone is insufficient to demonstrate health benefits of dietary supplements,” she added.
Source: International Journal for Vitamin and Nutrition Research
2021 Mar 1;1-11. doi: 10.1024/0300-9831/a000701. Online ahead of print.
A beneficial cardiometabolic health profile associated with dietary supplement use: A cross-sectional study
Authors: Jacques PF, Rogers R