How Identification of Genes and Genetic Expression Can Contribute to Nutritional Assessment

One change in a genome (single nucleotide polymorphism) isn’t necessarily the cause of a disease but can be a predisposition. So if nutrition can affect a single nucleotide can it be said that they can effect disease in both a positive and negative manor.

Gene-environment interactions: how the same environment effects different genotypes, also how different environment effects people with the same genotypes.

Obesogenic: how ones surroundings or stimuli contribute to becoming obese. Could be that ones environment can effect multiple genes and these genes predispose a variety of people to becoming obese. It is noted that it is possible that these external stimuli may not contribute to obesity and are just inherently going to become obese. Another category is that in a permissive environment one person will become obese and another will not due to being “genetically resistant” to obesity”. Those that are somewhat genetically predisposed to becoming obese but become obese due to a obesogenic environment (specifically food). The article wants to not the connection between ones genes and diet. The thing about food is that we have to eat, and the obesogenic environment is everywhere it seems. This factor should be pertinent given it is the environment we can control and study quite easily; we eat throughout our lifetime and given it can affect our genes it is something to consider in pre-disposing people to certain diseases. The article also notes “metabolic imprinting” which makes people more or less sensitive to diet altering gene alterations and presentations. This being another factor to consider when seeing the effect of diet on genes.

Given that nutritional assessment help identify malnourishments and or people who are at risk of becoming malnourished. Understanding how ones genetic makeup helps the clinician understand that the same recommendation to 2 different people with the same deficits may not react the same way to the same recommendations. This is very cool, it is then much more necessary to take a good history of each person and to understand their phenotypic results. To understand that genetics play a role in how a person responds to diet changes will help the clinician not be so close minded that one intervention works best.

For example, let us say that 2 obese people come to you for advice with the same health issue and diets. They are eating non-nutritionally dense foods and you recommend to both clients the same regiment of nutritionally dense foods and less of the other. One client is losing weight and seems to be getting healthier whereas the other has no change. If the clinician knows that there could be a possibility of genetic predisposing that alters how a person responds to diet change then the clinician can alter their diet recommendations quicker rather than pondering on the idea that “this should have worked for the client, maybe he’s not listening to my recommendations. ” This new way of thinking can alter ones nutritional assessment much more quickly allowing patients to get better quicker or seek other people who are better suited for such situations.

Nutrients, nutrition, and genes

Nutrigenetics: “personalized nutrition” since people have different genes then helps one avoid recommending the same nutritional advice to different people with the same health issues. Goals of nutrigenetics: find out genetic variance and how they can cause differences in responses to certain foods and nutrition changes. “Nucleotide variants within these, that are associated with the differential responses to nutrients. On the other hand nutrigenetics focuses on the effects of nutrients, both micro and macronutrients on the genome, proteome (protein expression), and metabolome (small molecule chemicals within the body). ”

Gene-nutrient interaction:

1. SNP’s that control how a nutrient is used in the body
2. A change in diet can alter how these SNP’s effect the body.
3. How nutrients physically effect gene expression.

This being said, diet affects the phenotypic response to a genotype. Given this statement: when a doctor prescribes nutritional changes then he must note or understand that these food alterations can and will in some way effect physiological response by effecting genes indirectly or directly. Very cool stuff, it is noted since diet will effect genes then the following can be effected: “metabolism, cell cycle/differentiation and inflammation. ” Which are applicable to the start and continuation of diseases. It is noted that dietary guidelines have not note of genetic varience amongst the population, this being said that people with the same health issues will not response the same given their SNPs. They used an example of the M235T SNP which is a change in the angiotensinogen gene. A blood pressure response may be different given this single nucleotide change and can be considered as to why someone may have a change in Blood pressure due to a change in dietary fiber. This can be applied to a patient that needs a change in their dietary fiber intake but may be cautious knowing that they have heart and or vascular issues.

Another gene that was discovered to be effected by nutritional changes is the VDR (vitamin D receptor gene). Caffeine intake by elderly women had marked loss in bone loss compared to the women that did not consume a certain amount of caffeine. Another study noted a similar phenomenon in the same gene, the VDR gene is in control of making proteins that are in relation to osteoblastic activity due. Knowing the results of these studies, a practitioner may be weiry to recommend caffeine to either an elderly woman or postmenapausal women who are already showing signs of bone loss.

The study found out that with an increase in caffeine, specifically; post-menopausal women, in this study had a higher rate in loss of bone density. Having a good understanding of such interactions between foods and genes can aid in patients getting healthy results quicker and perhaps help avoid detrimental side effects even though you as the doctor are prescribing these food to help with the patients’ health. Both of these examples showed some of the detrimental side effects of offering certain nutritional advice, but this is just a small portion on how nutrition plays a role in genes and their effects of physiology. If a patient has a SNP in the gene that helps manage interleukin-6, then the inflammatory response provided by this provided has shown to be congruent with increased coronary heart disease. To counteract this gene variance, it is suggested to add omega-3’s into the diet.