Fat stores energy, creates leptin and somehow stores toxins. Could the toxins in body fat prevent fat loss as a measure of protecting the body? Also would you need to remove those toxins if this is the case?
asked byprimallykosher (4131)
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on July 14, 2012
at 11:09 PM
I think this idea is really interesting and it makes sense to me. I went looking for evidence:
This study involved baby rats, so obviously it's not the best one to look at but it had interesting findings. Two groups of rats were formed, one group was exposed to PCB (which is a toxin with a strong affinity for storage in fat tissue) and the effects on leptin and thyroid hormone were measured:
"Leptin concentrations were significantly depressed in 15-day-old animals exposed to PCB when compared to same-aged control animals". "We speculate that the accumulation of fat-soluble PCB in adipocytes may be sufficient to cause these alterations".
This study examined the correlation between apparent PCB exposure and adiponectin levels in obese women. Adiponectin is secreted mainly by fat tissue which has been clearly shown to benefit insulin sensitivity and possibly obesity. This was observational, so no causation can be determined, but the researchers reported the following:
Plasma levels of total adiponectin...significantly negatively correlated with plasma levels of PCB 153 in OB (OB=obese women). "Our results may suggest suppression of adiponectin by PCB 153 in obese women under non-energy-restrictive regime".
Perhaps unsurprisingly, PCB exposure has been linked to diabetes.
This study, utilizing mice and in vitro trials, concluded the following:
"Our findings suggest that PCB-77 may contribute to the development of obesity and obesity-associated atherosclerosis"
Finally this study found a correlation between PCB exposure and waist circumference.
So PCB's, which are stored in fat tissue, seem to promote weight gain, though I'm aware these studies aren't slam dunk evidence. But they're interesting.
Moving to organochlorines, another toxin which is stored in fat; this review paper had some really interesting things to say, including this:
"Most of us have been exposed to organochlorines found in pesticides, dyes, solvents, etc., and we contain residues in our adipose tissue, where they are preferentially stored. Thus, the obese tend to have increased organochlorine concentrations compared to lean individuals ...organochlorine concentration has been correlated with decreases in triidothyronine (T3) concentration and resting metabolic rate . This is also associated with a reduction in activity of the skeletal muscle oxidative enzymes that normally are involved in fat oxidation ".
The paper explains that organochlorines are stored in fat and during weight loss are released into the blood where they exert negative effects on metabolism.
This study followed 90 people for 20 years, measuring their markers of health and apparent exposure to persistent organic pollutants (POP's), finding a correlation between exposure to POP's (including certain organochlorines and PCB's with 7 or more chlorines) and future BMI. They also discussed (but did not conclude) possible mechanisms:
"Chemicals may cause obesity by altering homeostatic metabolic set-points, disrupting appetite controls, perturbing lipid homeostasis to promote adipocyte hypertrophy, or stimulating adipogenic pathways that enhance adipocyte hyperplasia during development or in adults,"
Bisphenol-A is a fairly well known chemical found in canned food and the like and has an affinity for storage in fat. This study reported the following:
"BPA at environmentally relevant doses inhibits the release of a key adipokine that protects humans from metabolic syndrome. The mechanism by which BPA suppresses adiponectin and the receptors involved remains to be determined"
In mouse studies, BPA exposure may cause or increase diabetes and obesity. Bpa may also increase the inflammatory adipokines interleukin-6 and Tumor Necrosis Factor-alpha, which evidence is beginning to casually link to insulin resistance, as well as other negative health effects.
Well, I didn't get to the synthetic estrogens, but I think this makes a clear case that fat stored toxic chemicals can hinder weight loss. Some evidence suggests their release into the blood during weight loss is largely what causes this and that being stored in fat is actually protective, but results are mixed. It's all hard to say, but either way such compounds are worth being aware of. More research into how to avoid and deal with such chemical exposure and fat storage will likely be good for aiding in weight loss efforts.