I found some interesting studies that attempted to track the association between adipose tissue concentrations of conjugated linoleic acid, dairy intake, and diabetes risk.
are dozens of studies evaluating the effect of dairy consumption with risk of diabetes, with mixed results. Low-fat dairy is superior. But the question I have been asking is, is the effect of CLA in dairy products preventive of diabetes risk. Here’s what I found.
CLA supplementation may be a horrible idea
A study involving 38 young and otherwise healthy men measured lipid peroxidation for 5 weeks in a double-blind randomized trial. They were fed CLA oil. Lipid peroxidation increased 83% by the end of those five weeks in the CLA-oil group, and returned to baseline levels within two weeks of study completion.
Another study involving men with abdominal obesity also found increased lipid peroxidation (measured with the same technique), after CLA supplementation. EEK! I used to take this stuff. The consequences of this are not known. It may not be a bad thing, but right now it sounds like it.
Higher adipose tissue CLA reduces risk for diabetes.
In this study, a total of 1734 people with and without diabetes had their levels of CLA in their adipose tissue measured. It was found that more CLA in the adipose tissue was associated with a reduced diabetes risk. This may be one of the only studies to directly assess how much CLA you’re taking in and how that affects your risk of diabetes.
This study determined that milk fat consumption is positively associated with adipose CLA concentrations. Therefore, we can conclude that the greater adipose tissue concentrations of CLA in those with a reduced risk of diabetes was due to dairy consumption, supporting the hypothesis that fatty dairy products decrease diabetes risk.
This meta-analysis found that the inverse relationship between dairy consumption and diabetes was only seen with low-fat dairy. They did not measure adipose tissue concentrations of CLA, but this data contradicts the hypothesis we’ve formed here.
What does seem clear at least is that supplementing with CLA may be a bad idea. Perhaps our bodies just don’t know what to do with this naturally-occurring trans-fatty acid. I found another study that found worse glucose metabolism and insulin sensitivity after CLA supplementation.
Consumption of grass-fed dairy products is likely to increase your adipose tissue concentration of CLA, which could in turn have beneficial effects on glucose metabolism. In insulin resistance, the adipocyte leaks free fatty acids, which can induce insulin resistance. I wonder if the presence of CLA in the cell membrane or wherever it is may modulate this effect. It is worthy of further investigation but for now, stick to the whole food.