Are Fortified Foods Contributing to Rising Obesity Rates?

Obesity has more than doubled in prevalence in the United States since the 1970s.

Obesity has more than doubled in prevalence in the United States since the 1970s.

Around the same time that obesity rates started to rise, the 1974 mandatory flour fortification and Infant Formula Act of 1980 introduced many synthetic vitamins to American diets.

Was this just a coincidence, or is food fortification linked to obesity?

Obesity is paradoxically associated with low serum levels of vitamins, including folate and vitamin D. The August 2015 issue of World Journal of Diabetes includes a literature review suggesting that obesity may reflect chronic vitamin poisoning.

Investigators examined studies surrounding vitamin homeostasis, folic acid fortification, and low vitamin D to explain obesity’s association with low vitamin status.

Sweating was shown to be the primary pathway for excretion in those who consume excess amounts of water-soluble vitamins.

Obesity risk factors include black race, low birth weight/preterm birth, winter or cold weather birth, and physical inactivity. These same risk factors decrease skin conductance (and the ability to perspire), and consequently vitamin excretion from the body.

Excess vitamins in the body were shown to have various detrimental effects. For example, vitamins degradation generates reactive oxygen species, which in surplus leads to insulin resistance.

In the case of obesity, degradation systems seem to be overloaded, as demonstrated by folic acid levels. Increased body mass index (BMI) is associated with lower folate levels with detectable un-metabolized folic acid in the serum. The researchers suggested that this drug-metabolizing enzyme system saturates in obesity.

Normal vitamin D levels are also hard to achieve in obese individuals, as large amounts are sequestered in adipose tissue.

This review suggests that decreased skin excretory function, rather than irregular vitamin D levels, influences major diseases. As a result, 25-hydroxyvitamin D status may simply be an indicator of excretory function.

Evidence shows that reducing vitamin intake and increasing sweat rates may resolve the vitamin paradox. The authors believe that obesity prevention should focus on reducing vitamin-fortified foods in the diet, especially in susceptible individuals with low excretory capacity.