The anti-oxidant vitamins are electron donors capable of decreasing the number of free radicals in the body, serum, interstitial spaces and even within cells where they are most dangerous. The mechanism for this has been worked out. Free radicals are usually multi-atom chemical substances which have lost an electron and become ionized, although some minerals can also exist as free radicals. The free radicals can take up electrons from any location where they can be easily accessed. Remembering that nitrogenous compounds (proteins) are highly unstable, they provide excellant electron donors for free radicals to ‘steal’ electrons from. This, of course breaks a peptide bond (the chemical reaction breaking the peptide bond is an oxidation reaction, and the free radical is reduced), producing two polypeptides (without the biological significance which made them proteins in the first place). If the proteins were structural, then structural damage results requiring repair using available amino acids. If the proteins were enzymatic, the enzymatic function ceases sooner than expected, and may compromise whatever function would have been supplied had the enzymatic function continued. The alternative to the damaging effects of free radicals is for an anti-oxidant (such as Vitamin C, Vitamin E, or beta-carotene) to intercept the free radical, reduce it (preventing damage), but this also oxidizes the vitamin (or other anti-oxidant) thereby destroying the anti-oxidant. This also explains why Vitamins A, C and E are needed on a daily basis rather than weekly as for most nutrients. Tobacco and tobacco smoke [first-hand or second-hand] contain “substances known to the State of California…” which can be absorbed into the serum from the lining of the respiratory system as well as the lining of the digestive system [not limited to the intestines] and which are very effective free radicals, so tobacco users [including ‘smokeless’ tobacco products, and even most products used to aid smoking cessation] require more Vitamin A, C, and E than do non-smokers (but non-smoking requires not inhaling second-hand smoke). There is little doubt that these processes (damage due to free radicals, and the capability of anti-oxidants to disable the free radicals) actually occur in living tissues. The claim that anti-oxidants can repair damage due to oxidation of essential chemicals can not be explained as easily as the protective role of anti-oxidants. Most of the mechanisms for causing the repair of the damage caused by free radicals involve known metabolic processes, so the anti-oxidant would have to be a co-enzyme for that particular metabolic process in order for the anti-oxidant to assist in the repair [not drive the repair]. The role of Vitamin C in lessening the symptoms of the common cold would have to be the reduction of bacterial or viral toxins by the anti-oxidant properties of the Vitamin C. This could serve, at best, to reduce the toxin concentration, and therefore the amount of damage inflicted by the toxins. Assuming that the role of Vitamin C in preventing the symptoms of the common cold is true [not a good assumption] rather than an example of the placebo effect [a much better assumption], the mechanism of action would have to be the reduction of critical biochemicals in the bacteria or viruses responsible for the common cold; and this has not been shown to happen in a living organism. Two minerals, Zinc and Selenium have been cited as minerals with anti-oxidant properties which could be effacacious in relieving cold symptoms. Unfortunately, if either of these minerals were to have this effect, the mineral would be oxidized from its atomic state [no charge on the atom] to a free radical, which in turn could inflict damage somewhere else. Since both Zinc and Selenium can easily become charged ions (a.k.a. free radicals), they happen to be rather toxic [Selenium, for example, is the active ingredient in ‘loco weed,’ which produces severe psychosis (brain chemistry) problems for cattle; Selenium also causes (pg. 23-9 in the text) abnormal brain function (irritability) in Humans].
We have already met the French Paradox (last lecture): the French eat delicious flaky pastries made with animal lard, and filled with dairy-based fillings, providing too much cholesterol and saturated fats [and should exhibit a high incidence of artherosclerosis], but are heart-healthy. They also drink too much [mostly wine, usually red wine]. So, we wondered, does drinking red wine allow them to completely ignore the USDA's food guide pyramid, without consequences? Since red wine appears to exhibit greater effacacy than do the white wines, and red wines are made from grapes with skins, and white wines are made from grapes with the skins removed, the obvious place to look for the active ingredient is in the skins. When we examined the grapes skins, we found a high concentration of anti-oxidants, such as reveratrol (see any of the Roizen & Oz books, and look up either red wine or reveratrol in the index). Similarly, the Italians consume large amounts of pasta made with animal fats (and whole grains) plus lots of tomato-based sauces & olive oil (an Ω-3 oil) [not to mention drinking more wine than most American health professionals consider reasonable], and remain heart healthy. Tomatoes turn out to be high in anti-oxidants, but at lower density then in grape skins. Turning our attention to the two large populations with the highest life expectancies [age at which 50% of the same aged population can be expected to die], Japan and Hong Kong, we find that they consume very large quantities of green vegetables which have been cooked quickly in hot Ω-3 oils [stir frying using a wok] so they remain crisp even after cooking, plus lots of Ω-3 fish (white fish). The darker green vegetables have the highest anti-oxidant density of all vegetables. The common feature of these diets is high anti-oxidants and Ω-3 oils. The obvious hypothesis is that the combination of anti-oxidants and Ω-3 oils cause the heart health needed to achieve long life expectancies and long life spans. Current research is testing this hypothesis [see below, § 3. Western Diet.
The popularity of the anti-oxidants led to similar claims for many other plant-derived chemicals
[given the catchy name phyto-chemicals]. Phyto-chemicals were [and still
are] heavily promoted by Herbalists. The Ethnobotanists (the Botany discipline which studies
“Folk remedies” from regional plants), Nutritionists and medical researchers interested in
wellness are currently examining the phytochemicals to determine if the health claims for them are
justified. Their results thus far have been sufficiently encouraging that the phytochemicals have
become credible enough to start appearing in Nutrition textbooks and lectures. However, all of the
research thus far (and it is currently “inconclusive”) suggests that the phytochemicals
taken as food (dark green leafy vegetables, cruciferous vegetables [broccoli, cauliflower, brussel
sprouts]) exhibit far better effacacy than do the plant extracts taken as supplements in tablet form.
Some of the supplement tablets show no positive benefits, while others show only slight effects
[below statistical significance]. Some authors are now speculating that the phytochemicals will
eventually be added to the list of nutrient classes important to optimal Human functioning. Although
I am not surprised that the effacacy of phytochemicals is higher from food than from tablets, I am
not prepared to accept the phytochemicals as nutrients [until more research supports the health
benefit claims for the phytochemicals]. I would like to see some explanation of the physiological
mechanisms by which they work.
The phytochemicals technically include all chemicals found in plants: the pigments & accessory pigments, enzymes & co-enzymes, hormones & hormone-like substances, cellulose & lignin in cell walls, the toxins that protect plants from insect [and other animals] damage & fungal diseases of plants, and even DNA. In practice, most of the “phytochemicals” with proposed health benefits are pigments, accessory pigments, enzymes, and co-enzymes [but a few are toxins]. One group of phytochemicals which are claimed to “speed up your metabolism” as a means of losing weight without changing either your eating or exercise habits are the co-enzymes of the electron transport system (where energy is finally captured as ATP). These claims are highly seductive, but your mitachondrial DNA includes all of the genes for all of these co-enzymes, and as a result every mitachondrion you own already has all the co-enzymes it needs (or can use); you could speed up your metabolism by growing more mitachondria [but you have to wait until the “Weight Management 2” lecture to find out how to do this].
footnote: the Welch's ads promoting their Concord grape juice cite reports from the USDA in support of their claims. You need to know that the USDA publishes pamphlets written by individuals not employed by the USDA, and not fact-checked by USDA personnel. The individual who wrote the pamphlets cited by Welch's is Welch's [the IRS promulgated requlations allowing treatment of corporations as individuals for tax purposes, because the IRS can tax income only of individuals; this requlation also causes corporations to be treated as individuals by all Federal agencies]. The pamphlets describing the anti-oxidant properties of concord grape juice were neither written by nor endorsed by the USDA, merely published by the USDA. This statement does not say anything about the accuracy of the information in the pamphlet, only the nature of the source of the pamphlet. Since Concord grape juice is made from grapes with skins included, the anti-oxidant levels are probably very high.
A recent article in the Proceedings of the National Academy of Sciences of
the United States [Carlotta De Filippoa, et al. 2010. Impact of diet in shaping gut
microbiota revealed by a comparative study in children from Europe and rural Africa, PNAS
August 17, 2010 vol. 107 no. 33: 14691-14696] suggests a mechanism which could explain how the
Western Diet contributes to a decline in Wellness.
“In this work, we compared the fecal microbiota of European children (EU) and that of children from a rural African village of Burkina Faso (BF), where the diet, high in fiber content, is similar to that of early human settlements at the time of the birth of agriculture. By using … rDNA sequencing and biochemical analyses, we found significant differences in gut microbiota [the bacteria found in the colons, particularly the ascending and transverse colons] between the two groups. … We hypothesize that gut microbiota coevolved with the polysaccharide-rich diet of BF individuals, allowing them to maximize energy intake from fibers while also protecting them from inflammations and noninfectious colonic diseases. This study investigates and compares human intestinal microbiota from children characterized by a modern western diet and a rural diet, indicating the importance of preserving this treasure of microbial diversity from ancient rural communities worldwide.” (Carlotta De Filippoa, et al, 2010.) Basically, De Filippoa et al are suggesting that the Western Diet has effectively “killed off” the normal bacteria in the colon, and replaced them with new bacteria which do not provide the same Wellness contributions as did the normal bacteria.
This also supports my hypothesis in the lecture on Anatomy & Physiology that the colon bacteria assist in extracting nutrients from undigested food.
Technically, all food from agricultural sources is genetically modified, because we have been using selective breeding to “improve” food organisms for at least 5,000 years. The opponents of ‘genetically modified’ foods are actually referring to genetic engineering, where beneficial genes from one species are spliced into the genome of another species. For example, some plants which were not Vitamin C sources have been genetically engineered to produce Vitamin C. The opposition to genetically engineered foods seems to have become a issue after a reporter in Europe used the expression “franken-tomatoes” to describe a genetically engineered tomato. This was, of course, a reference to Mary Shelly's famous book about a mad scientist who created a monster in his laboratory [the monster was not “Frankenstein;” the mad scientist was Dr. Frankenstein; in fact, the monster had no name but was called “Frankenstein's monster”], and conjured up images that struck fear in the minds of some readers. Thus far, most of the genetic engineering accomplishments have been to add the ability to produce toxins for the control of insect pests. You should know that one of the most effective insecticides known is nicotine; because the physiology of insect external respiration (breathing) is different from vertebrates, nicotine causes respiratory arrest in insects. A very effective means of getting rid of household ants is to put tobacco in a jar filled with water, and make a ‘sun tea’ from the tobacco. This solution can be sprayed around the foundation of the house, and ants entering or leaving the house will absorb the nicotine through their feet [remember I told you it could be absorbed from unusual surfaces], and go into respiratory arrest. The down side is that the pesticide applications has to be repeated if it rains. I have successfully gotten rid of ants over a three year period by this treatment. [this is intended to be useful trivia]. There is no evidence that GM foods are unsafe, but little credible evidence that they are safe [since the ability to produce toxins has been added to food plants]. I doubt that the controversy over GM foods will go away in most of your life times.
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revised: 11 Nov 2009