Dispelling nutrition myths, ranting, and occasionally, raving

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Will soy give you strong bones? Spoiler: maybe, if you’re a rat

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Recently there was a lot of criticism of a NYT article about what’s making us fat that was really about what diets might make mice fat. Along the same lines is this research from the University of Missouri that found soy diets might increase women’s bone strength.

The study was not on actual human women though, of course. No, this study’s participants were rats. These rats are apparently a good proxy for human women because they are selectively bred to have low fitness levels and, “average American women are relatively inactive both before, and especially after, menopause”. Essentially, both American women (particularly older women) and these rats are lazy so they’re totally interchangeable when it comes to research. As it’s much harder to get women to adhere to specific diets, and there are far more variable to control for and ethical considerations when it comes to human experiments, it just makes sense to use rats.

So, these rats were divided into two groups: one group was fed a corn-based diet (you know, just like the average post-menopausal American woman eats) and the other was fed a soy-based diet. The results showed that: “the tibia bones of the rats that were fed soy were stronger compared to the rats who were fed the corn-based diet, regardless of ovarian hormone status”. Leading to the conclusion that: “Bottom line, this study showed that women might improve bone strength by adding some soy-based whole foods to their diet”.

To recap: rats were fed either corn-based rat food or soy-based rat food. The rats fed the soy-based rat food were found to have stronger leg bones. Therefore, human women can increase their bone strength by eating more soy.

This is ridiculous. We are not rats. We do not live the same lives as laboratory rats. We are not all sedentary. We do not eat the same food as laboratory rats. It is a huge leap to say that this study in rats shows that consumption of soy by women can lead to stronger bones. We are not eating a homogenous diet of corn-based rat food. The forms of soy we consume as humans are very different from that in rat food (e.g. tofu, soy beverage, tempeh, edamame, TVP).

Perhaps soy-based foods can increase bone strength in humans but this study doesn’t tell us that. This study tells us that this breed of rat has stronger bones when fed a soy-based diet than when fed a corn-based diet.


Aloe vera juice: another instance where natural may not be best

Aloe vera

The CSPI recently released a statement deeming aloe vera beverages unsafe to drink. This statement was based on research by the US government. The CSPI doesn’t provide a link to the research but I believe that it was this rat study published in 2012. As you know, I’m the first to be skeptical of any mouse or rat research. After all, these species are very different from humans and results seen with them does not necessarily translate to similar results seen with humans. However, this study does give me pause to reconsider consumption of aloe vera juices.

There has been limited research on aloe vera juice to date. However, the little research that does exist seems to lend support solely to the topical application of aloe vera. I might add, that there is conflicting research as to the wound healing properties of aloe vera. It appears that in some people topical application of aloe to cuts may actually exacerbate the problem and delay healing. Oral consumption of aloe vera is also not recommended for pregnant women as it can induce contractions.

The current rat study was conducted over the course of two years. During which time the rats were given water containing either no aloe, 0.5, 1, or 1.5% aloe vera. I’m a little unclear as to whether or not the rats were provided with any beverages besides the aloe vera laced water and how much aloe vera these concentrations would translate to for human consumption. I do think that these things matter when drawing conclusions from the results as we know that excessive consumption of anything is bad for you and it may be that the higher concentrations would be far more aloe vera than anyone would realistically consume. However, it’s very interesting to note that no intestinal tumors were seen in the rats consuming the 0 or 0.5% concentrations while a significant number of rats consuming the 1 and 1.5% concentrations developed intestinal tumors. Even if these rats were especially susceptible to intestinal tumors (which as far as I can tell they aren’t, although they are susceptible to liver carcinomas) you would then expect to see intestinal tumors developing in all of the groups, not just those ingesting the higher concentrations of aloe vera.

The rats were given aloe vera whole leaf extract which might also have played a role in the negative findings. It’s possible that different results might be found for the consumption of just the inner-fillet. Regardless, until further research is done, you might want to think twice before consuming aloe vera juice on a regular basis. Just because it’s “natural” doesn’t mean it’s good for you.