Phthalate, antibiotic levels plummet after five-day vegetarian diet.
Ji, K, YL Kho, Y Park and K Choi. 2010. Influence of a five-day vegetarian diet on urinary levels of antibiotics and phthalate metabolites: A pilot study with “Temple Stay” participants. Environmental Research. http://dx.doi.org/10.1016/j.envres.2010.02.008.
There are thousands of chemicals in the modern environment. Scientists have found that many of them are present in measurable levels in people.
Diet is believed to be one of the main sources of exposure to some of these potentially dangerous chemicals. With every meal, consumers may be unwittingly exposed to chemicals used while growing, processing and packaging food. These chemicals, in turn, can affect the body in many ways, from disrupting hormone action to impairing cognitive function to increasing the risk of obesity.
To date, little research has looked at exactly what chemicals routinely enter the body through food, at what levels, and whether exposure to these chemicals can be reduced through dietary changes. One innovative study on pesticide exposure through food found that after replacing school children’s conventional diets with organic diets for five days, levels of pesticides in the children’s urine dropped so dramatically as to be undetectable until the conventional diets were reintroduced. Whether dietary changes can impact levels of other environmental chemicals in the body remains unknown.
Phthalates and antibiotics are both known to enter the body through food. Phthalates are a group of industrial chemicals that have been shown to alter hormonal activity in the body, affecting many body systems, including the reproductive organs and the brain. Phthalates are mainly used to keep plastics (like PVC) soft, and thus can enter the food supply during processing and packaging. They are also found in pesticides and can enter the food supply through that route. Little work has been done to assess the levels of phthalates in different foods; however, one extensive study found that levels of some phthalates are particularly high in fatty foods and spices because they tend to be attracted to fat molecules. It remains unknown how food affects the phthalate levels in the body.
Antibiotics can enter the body through food and water. Antibiotics are widely used on livestock and poultry to keep them disease-free and promote growth. As a result meat, and dairy products often contain measurable levels of these pharmaceuticals, with water supplies and plants secondarily contaminated. The extent to which the widespread use of veterinary antibiotics in the food supply may endanger human health and cause antibiotic resistance is currently under debate.
Given the potential health risks, a better understanding of dietary sources of antibiotics and their resulting levels in the body is important, particularly for those who want to limit their exposure through food.
Twenty-five participants lived in a Buddhist temple and adopted the monks' lifestyle – including their traditional vegetarian diet – for five days.
At the beginning of their "Temple Stay," participants completed a questionnaire about what they had eaten in the previous 48 hours. They gave a urine sample to provide information on level of exposure to antibiotics and phthalates before the program began. None of the participants had taken any antibiotics or pharmaceutical drugs in the previous month. After five days of following a traditional Buddhist monk lifestyle and diet, participants again gave a urine sample so that levels of chemicals in their bodies after the program could be assessed.
Because it is difficult to measure levels of phthalates directly, researchers typically measure levels of their breakdown products in the urine samples. In this case, the scientists looked at levels of six different phthalate breakdown products as well as concentrations of three commonly used antibiotics and two of their breakdown products.
The researchers compared levels of phthalates and antibiotics in the body before and after the program. They also examined how the foods eaten in the days prior to the start of the Temple Stay related to the before levels of chemicals in their urine.
Participants varied greatly as to which antibiotics were detected in their bodies at the start of the study. By the end of the study, in many cases, participants’ antibiotic concentrations were too low to be accurately measured. For those samples that could be measured, moreover, both urinary levels of the antibiotics and the estimated daily intake of antibiotics had decreased after the Temple Stay.
Every participant had measurable levels of all six phthalate breakdown products at both the beginning and end of the study. However, after the five-day program, levels of all but one had dropped significantly, as had the estimated daily intake of phthalates.
The researchers also found that the foods participants ate in the 48 hours before starting the program were related to the concentrations of antibiotics and phthalates in their bodies. Beef, pork and dairy were associated with starting urinary levels of the various antibiotics, suggesting that those foods may be major inadvertent routes of exposure to the pharmaceuticals. Similarly, levels of one particular phthalate breakdown product were related to number of servings of dairy products consumed in the previous 48 hours.
The dramatic reductions in antibiotic and phthalate levels resulting from the five-day Temple Stay program of lifestyle and dietary change suggest that the body’s chemical burden can be reduced even within a very short time frame.
At the same time, phthalates remained in the urine of all 25 participants, albeit at lesser levels, even after the five-day program. The finding reinforces current thinking that diet is an important source of phthalate exposure but not the only one. Other sources of exposure include personal care products, home furnishings and dust.
Antibiotic levels showed a more dramatic drop, suggesting that food is, in fact, the major route of exposure.
This study is among the first to look at how diet affects phthalate and antibiotic levels in the body and shows that reduced consumption of animal products may be important. However, it also leaves many questions unanswered. The specific type of vegetarian diet and the Buddhist monk lifestyle adopted by participants in the Temple Stay are not described in great detail by the study’s authors. Vegetarian diets can vary considerably and because no additional information on the Temple Stay diet was provided, it is difficult to make more specific dietary recommendations on how the public can reduce chemical exposures.
For instance, the authors don’t report on whether the Temple Stay diet was free of dairy products as well as meats. Whether the foods consumed by participants were mostly fresh and unprocessed is also an important question. When it comes to chemical exposures in the diet, the specific foods consumed may prove to be less important than how those foods are processed, packaged and prepared. Further research is needed to examine those issues, particularly in isolation from other lifestyle changes.
Aside from the dietary changes during the Temple Stay, the adoption of a traditional lifestyle during the five-day period may have also contributed to reduced chemical exposures in the participants, particularly phthalate levels. Although lifestyle factors likely played a lesser role compared to food, without knowing more about the participants’ living conditions and surroundings during the program, it is impossible to rule out the importance of phthalate exposure through the environment. Nevertheless, this initial finding provides strong evidence that dietary and other lifestyle changes can reduce exposure to a range of potentially harmful chemicals even on a very short time scale.
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Phthalates and antibiotics