As a follow up post to the study on organochlorines and vegan diets, MR posted two more studies on diets and body chemical load. The first study, which I am going to review in this post, looks at urinary levels of 3 antibiotics and their metabolites as well as the metabolites of 4 major phthalates. The second study he listed looks at the change seen with an organic diet in children.

Influence of a five-day vegetarian diet on urinary levels of antibiotics and phthalate metabolites: A pilot study with “TempleStay” participants

Antibiotic use is widespread in the animal farming industry, human exposure to such compounds can come through water source contamination and ingestion of animal products (negating the prescription antibiotics). Detecting the major sources for unintended human antibiotic exposure is critical due to antibiotic resistance and other adverse drug interactions.

Also, phthalates are a pervasive environmental contaminates with one major source of human exposure being diet, but these chemicals are also present in many products we use. In the CNN article, “5 Toxics that are everywhere: Protect yourself“, phthalates are the second toxin listed and they report, “Virtually everyone is exposed to phthalates”.

I think the most interesting part of this study, besides the results of course, is that the people being tested only changed their diets for 5 days. Only 5 days. Do note this study was conducted in Korea, but livestock in the USA are definitely given antibiotics too. Also, in the paper is a comparison to levels seen in Korea, USA, and Germany for curious readers.

The three antibiotics tested for were: sulfamethazine (SMZ), trimethoprim (TMP), and enrofloxacin (EFX). Four phthalates often reported in human samples were also testes for; these include: diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), di-isobutyl phtalate (DiBP), and di(2-ethyl-hexyl) phalate (DEHP). A total of 25 participants (16 M, 9F) completed a 5-day vegetarian program, and levels of these antibiotics and phthalates were measured before and after the 5 day diet.

Typical Tap Water and Meat Consumption of Participants Before Diet

Antibiotics:

All 3 antibiotics were measured in the urine prior to the diet, although none were over the acceptable limit. Levels of all three antibiotics were lower after the diet, with some people reporting significant drops in certain antibiotic levels. Take a look at the numbers below:

Phthalates:

The phthalates measured before the diet were notably higher than the values often seen in the US general population, researchers noted, but some variations in the levels are present. Also, while diet is one major route of phthalate exposure, house dust, personal care products, and medications are also exposure sources in humans. So, some differences seen in reported levels for different countries could be explained by different common mechanisms of exposure.Below is the before and after measurements of phthalates for the 25 participants.

Oxidative Stress:

The researchers also measured the concentration of a urinary bio-marker for oxidative stress before and after the program, and found significant differences in the before and after values. Graph below:

Conclusion:

Based on the finding from this 5-day study, the researchers conclude that even a short-term dietary shift to vegetarianism can reduce dietary exposure to antibiotics and phthalates in the general population. In addition, oxidative stress levels were also seen to decrease.