Friday, November 9, 2012

Are vegetables good for you?

Before I begin, let me briefly talk about my biases. I would like to emphasize that I always loved eating vegetables. Even as a child, I enjoyed eating the lowliest, most hated of vegetables, including spinach, broccoli, peas, turnips, and just about everything my talented cooks of vegetarian parents offered me. Later I discovered, quite by accident, that my most acute health problems could be completely alleviated by going from a very low carbohydrate diet that included large portions of non-starchy vegetables, to an essentially carnivorous one. However, I mostly have assumed that this drastic health improvement has been in spite of avoiding vegetables. I have been more likely to hypothesize that this difference is down to extreme carbohydrate intolerance, a need for a particularly deep therapeutic level of ketosis, or that I perhaps have some micro-organism invading my body, such as candida, that will flourish to my detriment even on cabbage, but will leave me alone if I eat only meat. More recently, and rather reluctantly, I have had to examine whether, in fact, vegetables themselves, or at least some of them, are what is causing me harm.

In this post, I want to point to two sources that have helped me understand and embrace the idea that vegetables not only are not necessary for good health, but they may actually do harm in many people.

The first is a curious small study from 2002 in the British Journal of Nutrition. The point of the study was to see if the anti-oxidants in green tea have a positive effect on oxidative markers of stress. In order to make sure the effect was coming from the tea, they removed all fruits and vegetables (except potatoes and carrots) from the subjects' diets. The researchers didn't find any long-term effects from the green tea extract, but they did notice something interesting. The removal of flavonoid containing elements of the diet did improve those markers. A "decrease in protein oxidation, in 8-oxo-dG excretion and in the increased resistance of plasma lipoproteins to oxidation in the present study points to a more general relief of oxidative stress after depletion of flavonoid- and ascorbate- rich fruits and vegetables from the diet, contrary to common beliefs." In other words, it appeared in this study that not eating fruits and vegetables was better for the participants than eating them. If nothing else, this must give one pause.

The second I came upon just this week. At the 2nd Annual Ancestral Health Symposium 2012 (AHS12), Georgia Ede, M.D. gave her presentation titled "Little Shop of Horrors? The Risks and Benefits of Eating Plants". In it and on her website, she points out that there are no studies that she could find (and the above is the only one I know of) that actually compares diets with and without vegetables. The studies that she did find that showed positive benefits to eating vegetables are all flawed in some way such that it can not be determined which aspect of the intervention gave a positive benefit. For example they had people eat more vegetables and less refined sugar, or eat more vegetables and exercise more. Moreover, the only studies she found that did not have these confounders, had negative results, that is, they did not show the benefits the researchers were expecting. Of course, this is only absence of evidence, but with the extensive promotion of vegetables that we are exposed to so vigorously, one would hope to see something more concrete behind it.

Dr. Ede notes that there have been groups in the past that survived fine without vegetables. She makes cogent arguments against the assertions that fiber is beneficial, and that vegetarians are healthier than non-vegetarians. She shows that micronutrients are more abundant and/or more bioavailable in animal foods than in plants. Yet the most important insight she provides from my perspective is that there are many compounds in plants that function as protection for the plant, to prevent it being eaten. Even though many people can tolerate them at low levels, in high doses (or low doses for sensitive individuals) they are at best double edged swords, and at worst harmful. This is true even of compounds that have been touted as health-promoting, such as anti-oxidants.

She promises to write about many classes of toxins, and the first article has already been written. It describes the problems with brassicas (a.k.a. cruciferous vegetables). When I was on a simply low-carb diet, instead of a "zero-carb" diet (that's a bit of a misnomer, since there are trace carbs in meat, and I sometimes eat liver or cream, which have a bit more) I ate a lot of those, because they are very low in carbohydrates. As she claims seems to be the pattern, the ingredients in brassicas that are advertised as fighting disease, also cause problems, actually poisoning mitochondria, generating ROS's, and more. I recommend reading her post, and the rest of her site.

I'll leave with a quote that particularly struck me from the AHS talk:

26:37

"[P]erhaps these compounds are really only irritants that we've had to evolve to deal with because we happen to eat them, and maybe [it's not the case] that they're actually good for us."

9 comments:

  1. What about coconut oil and palm oil. I don't eat the stuff, but I have a couple gallons of each left over from when I used to. I have been using it as a lotion, but now I'm wondering if that's not such a good plan. I have enough to turn into soap: what do you think, would it still be toxic as soap?

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    1. The palm oil is unrefined and very strong in odor and dark in color, so I am particularly concerned about what could be in there.

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    2. Hi, Robert. Sorry for the delay in answering.

      This is a great question. I have tended to give coconut oil a pass, because the fatty acid profile is so favourable, and I understand that palm oil is similar.

      The first year or so that I ate carnivorously, I did not eat CO, but I have eaten it regularly since. It does not seem to have an adverse effect on my mood, but it is quite plausible that it is perpetuating my rosacea, which did heal quite a bit when I started, but has been worse lately.

      CO has a lot of salicylates in it, and some people feel that salicylates worsen rosacea.

      So I'm going to try eliminating it again, and see if that helps.

      Thanks!

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    3. It could be argued that coconuts evolved anti predatory defense was armor related rather than biochemical in nature.
      Besides humans I can only think of the coconut crab, and humans actively propagate the species so little selection pressure.

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  2. Hi
    Unrelated to the core point of your argument just an observation:

    "the extensive promotion of vegetables that we are exposed to so vigorously":
    this may seem extensive compared to what it used to be but surely given that subsidies are handed out much larger percentage to meat/dairy/cornfeed than to vegetables, and with all the weight of a meat-centric world-view where burgers and barbeques and turkeys are deeply embedded in the culture I am not certain the exposure to vegetables comes anywhere close to that of animal products. It may be more apparent because there is a relative increase in vegetable awareness but compared to the mostly subconscious thus very strong message of a traditional diet I don't think there is a balance.

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    1. Hi, Jani.

      Certainly meat is a regular part of our cultural experience. I don't know the details about subsidies, but I agree they would constitute a measurable endorsement. Nonetheless, we are bombarded with campaigns that claim that meat is not healthy but that vegetables are; that we need to eat 5+ servings a day for health, etc. Meatless Monday is a thing. Wheatless Wednesday is not, let alone Fruitless Friday.

      As to what is considered normal, at least where I live, there are plenty of vegetarian restaurants, and certainly vegetarian options everywhere. If you tell someone you are a vegetarian, they don't question you, and they know how to help you. To a lesser extent this is even true of vegan requirements.

      When I go out to restaurants I sometimes have to explain myself several times. I am very explicit ("I eat only meat and fat.") Then I will still get asked if I want some random vegetable, and even then half the time the plate still comes with an orange slice or pickle on it.

      Yes, the mainstream assumes that meals often include meat, but essentially no one imagines that a meal could not include something that's a plant.

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  3. I have struggled with all foods except animal. Even low carb ones. They caused tons of problems. I felt depressed as eating broccoli made me feel awful as much as wheat and dairy did. Thank goodness no issues with just meat!

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  4. I am another reader who eats just meat and fat because I have found all plant foods and spices to be problematic to my gut. I have been eating this way for quite a few years now. I feel and look great. I am much happier. Life is easier. And I don't have toe cramps anymore! I used to get them all the time when I ate plant foods.

    I eat locally raised, pastured meats, dairy and eggs, fats, and wild caught seafood. I eat organ meats on a regular basis, including sweetbreads from time to time for vitamin C. The only supplement I feel that I probably need is vitamin D, since I live in a northern climate and am not able to get much (if any) vitamin D from sun exposure.

    Thank you for this article, and the great site.

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    1. Hi. I'm glad to hear about your success. Thanks for writing!

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