Archives for: August 2010
QUESTION: Are you familiar with the other systems of metabolic typing? By this I mean the acid-base balance system and others (fast/slow oxidizer, etc.) Can they be used to improve the accuracy of the your own theories?
ANSWER: There are several other systems of 'biotyping' in the popular diet literature, including those that you have mentioned, the doshas of Ayurveda, and a few others.
Although I cannot prove that these other systems are without some value, it is a fact that none of these systems of 'metabolic typing' are represented in the scientific literature. Not a single study exists that would serve as a logical starting point from which to draw conclusions about something as important as an individual's lifestyle.
Not looking so good for metabolic typing research.
In contrast, we could search the medical databases, such as PubMed, OMIN or Ovid and find thousands of scientific articles on the phenotypic aspects of the blood group and secretor subtypes. In addition, the blood groups have had their genetic basis well determined, as well as many disease susceptibilities. In contrast, a search of the medical databases using keywords such as "fast oxidizer" or "blood acid pH" or "metabolic typing" does not yield a single scientific study, and no gene has ever been identified as a source of these distinctions (an important distinction, since without a genetic basis for transference to offspring, you have nothing better than a collection of random occurrences.)
Same for fast-oxidizer research.
Blood types are much more useful. Blood type virtually never alters over your lifespan, the testing is quite easy, inexpensive and the determinations virtually fail-safe.
On the other hand, the most stringent string search for studies on ABO blood group yield over 10,000 articles.
There are even over 1000 published studies on secretor status.
Finally, one should be wary of proponents of metabolic typing, including doctors, who disparage the significance of the blood groups. Many doctors offer metabolic typing as part of their own marketable services, and the large universe of blood type dieters offers an attractive potential market. On the other hand, recommending that a patient visit a local blood bank and library is not as likely to help pay the bills at the end of the month.
STUDY: Suppression of breast cancer cell growth with grape juice.
JOURNAL: Pharmaceutical Biol., 36:53-61, 1998.
AUTHORS: Chen, S., Sun, X.-Z., Kao, Y.-C., Kwon, A., Zhou, D., and Eng, E.
ABSTRACT: Breast Cancer Prevention with Phytochemicals in Grape Juice
Since phytochemicals such as flavones have been shown to be effective inhibitors of aromatase, it is hypothesized that by inhibiting aromatase/estrogen biosynthesis, fruit juices which contain flavones are chemopreventive agents for breast cancer. We have initially evaluated the hypothesis by determining whether fruit juices repress aromatase activity. Our experiments revealed that among seven fruit juices tested, red seedless grape juice was most effective in inhibiting the activity of human placental aromatase. Preliminary studies with a nude mouse model have also been performed to determine the action of grape juice in vivo. For this model, tumors form within one month after inoculating MCF-7aro cells, aromatase expressing breast cancer cells, into eight-week old female nude mice, and tumor formation can be suppressed by injecting the animals with aromatase inhibitors such as 4-hydroxyandrostenedione. We have found that the average tumor size in mice fed (by gavage) with 0.5 ml of grape juice/day is 30% that of the animals not fed with grape juice.
Based on results generated from our laboratory, we propose that grape juice is a useful chemopreventive agent for breast cancer by suppressing aromatase/estrogen biosynthesis. We hope that a breast cancer prevention strategy using grape juice can be developed based on results generated from the proposed investigation. Experiments are being designed to determine the optimal conditions for achieving breast cancer prevention. Furthermore, we will determine the scientific basis as to whether grape juice prevents the initiation and/or progression of breast cancer or eradication of cancer cells by acting as an aromatase inhibitor using two animal models, nude mice inoculated with MCF-7aro and the NMU-induced tumor model in rats. In addition, experiments will be performed to identify the active components in grape juice that inhibit aromatase. The latter experiments not only will lead to an understanding of the molecular basis of aromatase inhibition by grape juice, but also allow us to design a potent and selective breast cancer prevention strategy.
COMMENTARY: Aromatase converts androgen to estrogen. Aromatase is expressed at a higher level in breast cancer tissue than in benign tissue. In estrogen biosynthesis in tumor tissue has been shown to play a role in promoting tumor growth. Suppression of estrogen biosynthesis can be achieved by the prevention of aromatase expression in breast tumors or by the inhibition of aromatase activity. There are several natural products that inhibit aromatase, but grape juice certainly can rank as among the most tasty.
QUESTION: I am A and hypothyroid. You state soy is excellent for A's but, from my researching and reading, most sources state that hypothyroid should avoid soy. Any suggestions as how to get protein and vitamins without using soy?
ANSWER: In a recent response to many of the off-handed accusations about the effects of soy on the thyroid Clare Hasler, Ph.D., one of the world's experts on soy and human nutrition had the following to say:
"There is no convincing evidence that soy protein has an adverse effect on thyroid function, particularly at the moderate level of consumption (25 grams) that would occur due to the approval of a health claim for coronary heart disease.
There is evidence that animals exposed to large amounts of soy protein (e.g., 40%) will develop goiter, particularly when fed an iodine deficient diet (Kimura et al., 1976; Filisetti and Lajolo, 1981). The mechanism for this effect can be explained by the fact that the principal isoflavones in soy, genistein and daidzein, have been shown to inhibit thyroid peroxidase (Divi et al., 1997) and 5'-deiodinase (Cody et al., 1989), key enzymes involved in thyroid hormone biosynthesis. The inhibition of these enzymes results in decreased levels of circulating thyroid hormones (e.g., T4 and T3) which leads to increased secretion of thyroid stimulating hormone (TSH) by the anterior pituitary. The increased levels of TSH provides a growth stimulus to the thyroid, resulting in goiter. It must be emphasized, however, that this occurs only with large amounts of soy isoflavones in the diet and/or when the diet is low in iodine. Furthermore, soy isoflavones are not the only dietary flavonoids that can inhibit thyroid peroxidase. A variety of other flavonoids have also been shown to be even more potent in inhibiting the activity of this enzyme, including kaempferol, naringenin, and quercetin (Divi and Doerge, 1996) . Such flavonoids are widely distributed in plant-derived foods and would be consumed daily at relatively high levels (possibly up to 1 gram or more per day) by vegetarians or semi-vegetarians, yet such individuals do not have a significant increased incidence of goiter. Goiter has also been reported in infants where soy has served as the sole source of food (Hydovitz, 1960). However, this situation is hardly comparable to adults consuming soy protein in moderate amounts as a means to lower total or LDL cholesterol levels.
In sum, soy products have been consumed as a dietary staple in Asian countries for hundreds of years with no significant occurrence of goiter in that population. Goiter is primarily due to a deficiency of dietary iodine, not the consumption of moderate amounts of soy protein incorporated into a nutritionally sound diet. That goiter would result in adults consuming 25 grams of soy protein per day in response to an approved health claim for coronary heart disease is ludicrous."
In essence, it you don't consume 40% of your body weight in soy protein daily, you've not got much to worry about.
Cody V, Koehrle J and Hesch RD. Structure-activity relationships of flavonoids as inhibitors of iodothyronine deiodinase. In: Environmental Goitrogenesis, Gaitan, E. (ed), pp. 57-69, CRC Press, Boca Raton, FL, 1989.
Divi RL, Chang HC and Doerge DR. Anti-thyroid isoflavones from soybean. Biochem. Pharmacol 54:1087-1096, 1997.
Divi RL and Doerge DR. Inhibition of thyroid peroxidase by dietary flavonoids. Chem. Res. Toxicol. 9:16-23, 1996.
Filisetti TM and Lajolo FM. Effect of the ingestion of soybean fractions, raw or autoclaved, on the rat thyroid. Arch. Latinoam. Nutr. 31:287-302, 1981.
Hydovitz JD. Occurrence of goiter in an infant on a soy diet. N Engl. J. Med. 262:351-353, 1960.
Kimura S, Suwa J, Ito B and Sato H. Development of malignant goiter by defatted soybean with iodine-free diet in rats. Gann 67:763-765, 1976.
STUDY: Why is acute leukemia more common in males? A possible sex-determined risk linked to the ABO blood group genes.
JOURNAL: Ann Hematol 1999 May;78(5):233-6
AUTHORS: Jackson N, Menon BS, Zarina W, Zawawi N, Naing NN.
ABSTRACT: Acute leukemia is more common in males at almost every age, and this fact remains unexplained. A study was carried out in northeast peninsular Malaysia, where the population is predominantly Malay, to examine whether there was a difference in ABO blood group distribution between males and females with acute leukemia (AL). The ABO blood groups of 109 male and 79 female patients with AL (98 ALL, 90 AML) were compared with those of 1019 controls. In the control population, 39.7% were group O. Among males with AL, 39.4% were group O, whereas among females with AL, the proportion was 24.1% (p=0.03). The same trend to a lower proportion of group O among females was seen when the group was divided into adult/pediatric or lymphoblastic/myeloblastic groups, though these differences were not statistically significant. If these findings can be confirmed, they suggest the presence of a "sex-responsive" gene near to the ABO gene locus on chromosome 9, which relatively protects group O women against AL, at least in our population. The existence of such a gene might also partly explain why acute leukemia, and possibly other childhood cancers, are more common in males.
COMMENTARY: Here we again see the manifestation of ABO blood type in a much wider context than the simple manifestation of an antigen on a red blood cell (which, unfortunately, is all that they teach you in medical school). Gene linkage (the tendency of clusters of genes to transfer together) may help explain this phenomenon, since the O allele and the putative "protective sex responsive gene" probably only transfer together on the condition of the outcome of sex-determination (female).
STUDY: ABH blood group antigen significance as markers of endothelial differentiation of mesenchymal cells.
JOURNAL: Folia Med (Plovdiv) 1997;39(2):5-9
AUTHORS: Sarafian V, Dimova P, Georgiev I, Taskov H
ABSTRACT: The expression pattern of A, B and H blood group antigens was evaluated by staining frozen sections with specific monoclonal antibodies developed by us and using the indirect immunoperoxidase method. The expression of blood group antigens was ubiquitously upregulated in the endothelial cells of fetal organs. In the process of their differentiation to endothelial naive embryonic mesenchymal cells expressed cytoplasmic ABH antigens. They were assumed as products of the activation of the respective genes. ABH antigen expression was considered as suggestive evidence for the assumption that blood group antigens could serve as early immunomorphologic markers of endothelial differentiation of mesenchymal cells, thus specifying the location of future blood vessels. Extending the conceptual framework of blood group antigens' significance we consider them as being possibly involved in the process of fetal morphogenesis.
COMMENTARY: This study hypothesizes that a potential prime role for ABO blood group antigens is to act as markers of differentiation (the modification of body parts for performance of particular functions; the sum of the processes whereby immature and indifferent cells, tissues, and structures attain their adult form and function).
Thus ABO antigens acts somewhat as the artists' paintbrush or the sculptors' chisel, gradually giving shape to form, in this case by acting to point the way for the development of blood vessels in t he growing fetus, much like a surveying crew works in front of the builders -deciding where and how the road should be laid.
This also explains why ABO is so intimately linked to many of the early stages of tumor development, since a cancerous cell tends to lose differentiation, going back to a more amorphous, embryonic state. Since ABO plays such an important role at this stage in the healthy fetus, it is not too unreasonable to think it plays a similiarly important role in embryonic-like cancer cells.
However, don't ask you average clinician about this. He or she more often than not thinks considers blood type nothing more than a 'transfusion complication.'
STUDY: The ABO blood group gene: A locus of considerable genetic diversity.
JOURNAL: Transfus Med Rev 2001 Jul;15(3):177-200
AUTHORS: Chester MA, Olsson ML.
ABSTRACT: The blood group ABO gene shows considerable polymorphism in most of the 7 exons. Introns examined so far have also shown blood group-related polymorphisms, as has an upstream enhancer region. Several polymorphisms affect the specificity of the gene product (glycosyltransferase) and explain the occurrence of blood group A and B. Other mutations are presumed to alter the activity rather than the specificity of the enzyme and result in weaker A and B blood group phenotypes. In total, 27 A alleles, 15 B alleles, 26 O alleles, and 4 AB hybrid alleles are described and surely more will surface in the near future. Variation in geographic/ethnic distribution of allele frequencies is discussed, along with the confusing nomenclatures currently in use.
COMMENTARY: Just looking at the total number of potential alleles shows that the ABO gene locus (on chromosome 9) is the site of considerable variation. The genetic links beteween blood type are not commonly recognized in evaluating the blood type diet theory, but probably are the main reason biological values, such as stomach acid or intestinal enzyme levels, are known to value by ABO type.
The variations in geographic and ethnic distribution serve to support the premise than major variation in blood group gene distribution are the result of biological, environmental or climatic changes.