Newsletter #195

Good morning, humanOS friends! So today, we’re going to talk about tomatoes, and what sets them apart from a nutritional standpoint.

Why tomatoes? No particular reason, other than we happened to come across some juicy studies on them. In fact, tomatoes are an iconic summer vegetable, so from a seasonal standpoint I guess it doesn’t make a ton of sense to feature them in a January newsletter. But tomato products like sauce, puree, and paste are available year round, and oddly enough these are actually the best source of the beneficial compounds associated with tomatoes.

This is because tomatoes are a powerful illustration of how processing can, in some cases, enhance the health-promoting properties of specific foods. Tomatoes are probably best known for containing lycopene, and indeed they are perhaps the richest source of lycopene in the diet. However, studies have revealed that the human digestive tract is not able to release the majority of lycopene from raw fresh tomatoes - in fact, it may only be able to capture as little as 4%! The reason for this is that carotenoids like lycopene are tightly locked up with proteins in the plant matrix. However, when you finely chop up or cook tomatoes, that plant matrix is disrupted, releasing loads of lycopene that your body can use but not compromising any of the other healthy attributes of the food (fiber, vitamins, etc). In other words, you’re amplifying the very best aspects of tomatoes without losing any other good stuff or adding in bad stuff. Yay, technology!Of course, this principle only goes so far, and it ceases to apply when we are talking about ultra-processed products that incorporate tomatoes. If you scroll down to the nutrition facts and ingredients sections for Totino’s Pizza Rolls, it’s quite obvious: Products like this are far more energy dense, and the healthy components are overwhelmingly crowded out by highly refined sugars and unhealthy fats.

Food processing is not necessarily good or bad - we need to look at the purpose and extent of the processing, and how it influences the nutritional content of the final product.

Researchers examined dietary intake and coronary risk factors in a large cohort of 39,876 middle-aged and older women initially free of cardiovascular disease and cancer. After 7.2 years of follow-up, it was determined that women who consumed at least 10 servings of tomato-based products per week had a ~30% lower risk of developing cardiovascular disease. In another similar study, researchers followed 1,031 middle-aged men in Finland, but this time examined blood levels of lycopene and other nutrients rather than estimating intake from dietary data. After a median of 12.1 years, they found that men in the highest quartile of lycopene concentrations had 59% and 55% lower risks of ischemic stroke and any stroke, respectively, compared with men in the lowest quartile.

So why might tomato products be protective against cardiovascular disease? A meta-analysis of 12 intervention studies found that lycopene in doses of ≥25 mg daily (about the amount in one cup of tomato juice) reduces total cholesterol by about 7.5% and LDL cholesterol by around 10%. That may not sound like a whole lot, but it is actually comparable to the effect that is seen from low doses of statins in patients with slightly elevated cholesterol. And it doesn’t take long to realize this impact - one trial that gave tomato juice to healthy young adults for just three weeks showed a drop in LDL cholesterol of 12.9%. Practically drug-like effects without the drawbacks of drugs. As an added bonus, the meta-analysis also looked at trials examining the impact of lycopene on systolic blood pressure and found a significant blood pressure reducing effect (around −5.6 mm Hg) in individuals with hypertension.

Finally, this is probably the benefit for which tomatoes (and the lycopene in them) are best known. Researchers assessed dietary intake for a cohort of 47,894 men who started the study free of any diagnosed cancer. Over the course of about six years of followup, 812 new cases of prostate cancer were documented in this population. When the researchers analyzed the dietary data, they found that only lycopene intake, and specifically tomatoes and tomato products, were associated with lower risk of prostate cancer. Greater than ten servings of tomato products (including tomatoes, sauce, juice, and pizza) per week was linked to a 35% lower risk of prostate cancer, and a 53%  lower risk of advanced prostate cancer, compared to consuming less than 1.5 servings a week, with the strongest association found for tomato sauce. This is supported by a more recent meta-analysis of 30 studies, which found that processed and cooked tomatoes are correlated with significantly lower prostate cancer risk but no such association for raw tomatoes.

In movies and television series, war horses are often depicted as grand steeds, but apparently this is one of many cases where popular imagination is pretty far off from historical reality. A team of archaeologists recently analyzed the largest dataset of English horse bones dating between 300-1650 AD, found at 171 different archaeological sites. They found that horses during the period were often below 14.2 hands high (less than five feet tall!). Co-author Alan Outram noted that none of the almost 2,000 animals that were studied would have even been of the minimum size to serve as modern police horses.

This, of course, does not diminish the profound impact of the horse on society at that time and on the complexion of Medieval warfare - if anything, I’d say it makes it all the more impressive.

This week, we’d like to highlight our course on smoothies and phytochemicals. One thing to keep in mind, when talking about the impact of ultra-processed food, is that altering the structure of food isn’t necessarily a bad thing per se. In fact, certain forms of processing can actually enhance the health-promoting properties of whole foods in some cases. Smoothies are a great example. For instance, a recent study found that an apple and blueberry smoothie elicited a reduced glycemic response compared to an equal portion of whole apples and blueberries!

The course takes a deep dive into phytochemicals in plants, where they are found, their powerful health effects, and how intelligently-devised smoothies can help optimize our intake of these compounds. For more practical information on using smoothies to enhance nutrition, please refer to our How-to Guide for smoothies.

Thanks as always for reading! If you're looking for more juicy health studies (and occasionally random science or memes), be sure to check us out on Twitter on @humanOS_me. See y'all next week!

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