my brother in law, who became an MD last year, just sent an email to my parents saying they should switch their protein powder to a different “cleaner” brand with BCAAs. He said he is worried about these due to a possible association with increasing the risk of heart and kidney disease. He said he’s worried those BCAAs are a little toxic for the blood vessels. He says “everyone knows red meat is one of the worst things for your heart. It is also on of the richest dietary sources of BCAAs. While I cannot claim to know for sure that is the BCAAs that are responsible for this, I think there is enough reason to be suspicious. Overall, it’s a lot of work for your kidneys to help metabolize them, and they become pro-inflammatory as a result”. He cited this study https://diabetes.diabetesjournals.org/content/67/Supplement_1/455-P saying it’s a dog shit study because they didnt’ control for diet but they did control for obesity so there is a little bit of value here. He says not to worry about having been eating this protein for some time because he is confident that BCAAs are far worse for people who are sedentary compared to if they are active (which is the one thing I agree with). I don’t believe his information is correct, but can you confirm this? Do you have any studies that may prove this to be incorrect or not clinically significant that I can share with him? So far I’ve compiled the ones in the protein and kidney disease youtube video, but it doesn’t necessarily specifically talk about any deleterious effects from BCAAs.
Ask your BIL if he thinks BCAAs are only present in red meat and protein powder? Hint…they aren’t. Nearly all non-silk sources of protein have BCAAs.
Your kidneys don’t really metabolize BCAAs that much either, rather the skeletal muscle and liver are the biggest metabolizers. Also, the brain and fat tissue metabolize more BCAAs than the kidney does.That said, the kidney metabolizes BCAAs for fuel. Your BIL is probably thinking about filtration, one of the kidney’s jobs. At present, we have no evidence that high protein intakes (most protein is ~25% BCAA) harm the kidneys and multiple lines of evidence showing it does not.
The study provided does not show that a high BCAA or protein intake increases incidence of any disease, but rather that obese people have worse outcomes. Obesity also tends to impair BCAA metabolism a bit, though the clinical effect of this is still up for debate.
The red meat piece is annoying, as this is a complicated issue. Red meat is not really “bad” for the heart and the best data suggests that there is a small increased risk of colorectal cancer with elevated intakes of red meat (>3 servings per week). The saturated fat content of red meat varies by cut and if saturated fat is kept to 10% or less of total daily calories, it doesn’t appear to matter at all based on present evidence. In studies comparing high protein intakes in vegans and meat eaters there’s no difference in CVD, all-cause mortality, etc. when they eat the same amount of fiber. You can cite the EPIC-Oxford studies for this.
I’m not interested in having this debate with someone who isn’t here to make their case and provide actual evidence for the points.
Jordan, on the association between >3 serves of red meat and colorectal cancer, could this be due to reduced fibre intake in these individuals? Do the observational studies that find this association control for fibre intake? Even if they do, I would think that individuals eating a lot of red meat as well as ~800grams of fruit/veg a day would be rare, making an “all things equal” comparison unreliable. (Sorry to the OP for hijacking the thread).
Nearly all of these studies are observational, as they have to be in order to follow the participants long enough for the disease(s) to develop.
That said, the EPIC-Oxford -based papers I’m thinking of did not specifically look at colorectal cancer as an outcome, though about 20/30 studies looking at this particular issue- including some that correct for total fiber intake - find this association. That said, the increased risk may or may not be big enough to move the needle for some
