Frontiers in the Nutrition Sciences Proceedings of a Symposium (1989) / Chapter Skim
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The Genome: Nutrition and Human Variation
The Genome: Nutrition and Human Variation
Pages 32-41
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From page 32... ...
The HLA variants also show tremendous genetic variability. More recently, chromosomal variants have shown considerable variability at the DNA level.
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From page 33... ...
This can be observed in the case of a very simple genetic interaction of just two pairs of additive genes. For example, the variability of enzyme levels within the normal ranges often has a simple genetic basis, because different alleles at a Gene locus that specifies one structure or a given enzyme may be associated with slightly different mean enzyme levels.
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From page 34... ...
nontasting. PTC nontasting is an example of a common monogenic trait that makes a significant proportion of the affected population unable to taste bitter substances.
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From page 35... ...
deficiency, prolonged apnea from pseudocholinesterase variation, and various drug reactions associated with defective acetylation of drugs such as isoniazid. EXAMPLES OF THE INTERACTIVE ROLE OF GENETICS The concept of pharmacogenetics can also be applied to ecogenetics, that is, the interaction of specific genetic traits with any environmental agent to produce a given effect.
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From page 36... ...
Those people who are affected are homozygotes for a gene that facilitates increased iron absorption and is carried on the short arm of chromosome 6, which is closely linked to the HLA-A locus. The homozygous state affects about 1 of 600 to 1 of 1,000 individuals in the United States and Western Europe, indicating that about 10% of the population is a heterozygote for or carrier of the condition.
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From page 37... ...
have a higher mean blood pressure and a higher frequency of hypertension than those of European origin. ~ ~ ^^ ~ ~~ ~ recently Discovered ul~terences between black and white hypertensive populations include the absence of elevated red blood cell sodium and lithium countertransport in blacks -- a finding that is also common among white hypertensives.
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From page 38... ...
Various DNA markers of the apolipoprotein loci have been associated with hyperlipidemia and with coronary heart disease but the results have not always been consistent. Considerable research work is being carried out in these areas and is likely to clarify the exact contribution of genetic factors to hyperlipidemias.
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From page 39... ...
Another point bears on this issue of individual versus population recommendations. Some argue that a lowering of the cholesterol level of Western populations by dietary modifications would substantially reduce the frequency of coronary heart disease, regardless of genetic variaticholesterol level from 226 to 210 mg/dl, as might be achieved with dietary modification, would reduce the absolute risk of mortality from coronary heart disease only slightly.
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From page 40... ...
We taste things differently; we smell things differently and as noted earlier, it is likely that these differences influence the nutritional metabolic processes, requirements, and interactions that can lead to chronic disease. Judging from the frequency of genetic variants in enzymes and proteins and their effects on enzyme activity, significant variations in nutritional requirements or in genetic-nutrition interactions may often exist.
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From page 41... ...
Although we have an inkling of the extent and type of human variation, however, much more work is needed to elucidate the descriptive, metabolic, and biochemical bases of this genetic variation. Sensible dietary recommendations can be made for the general population, although we must not ignore individual needs.
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