|Choline, fiber, potassium, this meal has everything US citizens don't eat.|
While many studies have examined the differences in micronutrient intakes in various population subgroups, very few studies have compared the micronutrient intake status of overweight and/or obese with that of normal weight adults. A highly relevant distinction as it turns out.
In view of the fact that more than two thirds of the U.S. population is either overweight or obese and represents a population subgroup with higher risk of several chronic diseases, including cardiovascular disease and diabetes, one of the main goals of the latest reanalysis of data from the NHANES study included a differential analysis to determine, whether there are differences between lean and obese individuals when it comes to the amount of micronutrients they consume.
This subgroup analysis is also important, because scientists have repeatedly speculated that nutrient deficiencies may contribute to the rapid increase in US obesity rates over the past decades. In view of the fact that micronutrient deficiencies can occur as a result of both, an insufficient intake and in response to altered absorption and metabolism, the results of the study at hand may offer important insights into possible set screws that may help to prevent a further increase in the US obesity rate.
Lean vs. overweight & obese - is there a difference?
The researchers were also able to show that the proportion of adults with intakes below the EAR also differed significantly by body weight status (Figure 2). In that, a significantly greater percentage of obese adults compared to normal weight adults had intakes that did not meet the EAR for vitamin A, vitamin C, vitamin D, vitamin E, calcium, and magnesium (p < 0.01).
What about supplements? The study at hand evaluated the total intake. It is thus not surprising that those US citizens who take multivitamins & co had a lower prevalence of inadequacy of micronutrients compared to nonusers. Furthermore Agarwal et al. were able to show that "supplement users are more likely to have healthier diets compared to nonusers" (Agarwal. 2014) - a result that is in line with results of previous investigations, by the way.
Since all three of them have been associated with metabolic and cardiovascular health, respectively, the insufficient intake of these allegedly "non essential" nutrients (this is why there is no RDA for them) could be as much of a problem as the lack of any of the literally vital vitamins.
In their discussion of the results, the researchers from NutrieScienceLLC highlight that their study is the first study reporting inadequate intake and high prevalence of micronutrient inadequacy in a nationally representative sample of overweight and obese U.S. adults using mean usual intakes determined by the NCI method.
- the intake of fruit and dairy was significantly lower among obese adults compared to normal weight adults, and
- the healthy eating index, a measure of how close someone eats to the dietary recommendation for obese adults was slightly but significantly lower compared to normal weight adults
|Figure 4: Usual Intakes of Parameters of Diet Quality of Adults (age 19 years) by Body Weight Status (Agerwal. 2014)|
"[...r]eported total carbohydrate and added sugar intakes were significantly lower than measured, whilst reported protein and fat intakes were not significantly different from measured " (Poppit. 1998).And Heitman et al. (1995) and more recently Meng et al. (2013) highlight that the degree of obesity was positively associated with underreporting of total energy intakes.
- Agarwal, Sanjiv, et al. "Comparison of Prevalence of Inadequate Nutrient Intake Based on Body Weight Status of Adults in the United States: An Analysis of NHANES 2001–2008." Journal of the American College of Nutrition ahead-of-print (2014): 1-9.
- Heitmann, Berit Lilienthal, and Lauren Lissner. "Dietary underreporting by obese individuals--is it specific or non-specific?." Bmj 311.7011 (1995): 986-989.
- Meng, X., et al. "Under-reporting of energy intake in elderly Australian women is associated with a higher body mass index." The journal of nutrition, health & aging 17.2 (2013): 112-118.
- Poppitt, S. D., et al. "Assessment of selective under-reporting of food intake by both obese and non-obese women in a metabolic facility." International journal of obesity and related metabolic disorders: journal of the International Association for the Study of Obesity 22.4 (1998): 303-311.