HOW GENES AFFECT HEALTH?
WHY DO OUR BODIES RESPOND DIFFERENTLY TO FOODS AND EXERCISES?
There is one in a trillion chances for you to have an exact look-alike of yourself living and breathing somewhere in this wide world. The uniqueness about you, however, does not stop at your facial features. It goes deeper than that and influences the functional aspects of your body.
Have you, for instance, ever thought that your perception of smell might be significantly different compared to other people? Or that the taste you perceive might not be what everyone else does as well? Because as it turns out, such differences have been confirmed to exist by Dr. Casey Trimmer in a very interesting research. Taste, it seems, really is subjective. ¹ (To some extent at least)
But that is merely the tip of the iceberg. What really has an impact on our day-to-day lives are the differences that exist at the level of metabolism, absorption, digestion, and immune function. These differences give strength to the idea that we should be moving away from generalizations in an attempt to personalize our approach to health and wellbeing.
AT THE LEVEL OF METABOLISM AND ABSORBTION
We differ a great deal in our response to food intake and the way we absorb and metabolize that food. This concept of unique metabolism is in some ways hard-wired within our genes. This also means that a diet that is easily digested by an individual may produce disease in another individual.
We all know how some people are especially lactose intolerant. This is due to the LTC gene which encodes Lactase, an enzyme that digests lactose. A lactose intolerant individual harbors a mutation in this gene due to which he is unable to digest lactose and develops symptoms of bloating and flatulence upon consuming milk. Pretty nasty eh? ²
DO WE ABSORB THE SAME AMOUNT OF FOOD?
We don’t. Surprise surprise!
A study conducted at Cornell University proves that individuals with genetic variants that contain more copies of a certain gene can gain a larger amount of glucose from a particular diet as compared to those who have fewer copies of this gene.
This can be attributed to the larger amounts of an enzyme “Amylase”, encoded by that gene, which breaks down a higher amount of starch in the diet. This, in turn, favors the growth of a family of bacteria in their guts that breaks down complex starch (which cannot be degraded by Amylase) into absorbable sugars. Sounds complex? You can read it in more detail here.³
THE UNIQUE CASE OF GREENLANDERS
It is a commonly observed fact that the environment influences gene expression to enable an individual to adapt. This principle has brought some startling changes in the genetic makeup of Greenlanders in the way they process food in their intestines.
A study of their genetic makeup shows that their intestines lack an enzyme, which breaks down complex sugars. These sugars travel directly to the intestine where they are metabolized to Acetate. Acetate, subsequently, decreases appetite, improves metabolism, and enhances immunity. This can be directly correlated to the fact that for Greenlanders, it’s hard to get fat. Call it nature’s gift if you will. ⁴
OUR LIKES AND DISLIKES
People belonging to a certain area have particular food preferences, aversions, and allergies. This can also be attributed to the environmental influence on genes.
For instance, some people like eating beets while others perceive their taste to be “earthy” and avoid them at all costs.⁵ Another common example is that Europeans have an increased propensity to develop Celiac disease if they take a diet high in Gluten.⁶
GAINING AND LOSING WEIGHT
It’s not all your fault. That’s right. Obesity, in many cases, is a heritable trait. And so is persistent leanness. Eating habits are to blame no doubt, but for some people, it might just be too easy to gain weight. ⁷
That doesn’t make it okay of course. The disadvantages to health that obesity brings with it will be just as impactful regardless of how easy it was for you to gain weight. But knowing that you might have such a propensity may keep you more alert at the dining table.
That’s not all though. Knowing how to lose weight might be just as tricky. Some diets may work for others but not for you. Some plans may be great for you but fail for others. For example, the weight-loss high-fiber diet, known as the “New Nordic Diet”, works only for those people who have the right combination of gut bacteria.⁸ Thus it is possible for you to continue to gain weight despite the high-fiber diet if you do not have the right mix of gut bacteria.
Nutritionists all over the globe have started to recognize these differences and hence the level of personalization is reaching new heights.
At the core of these differences lie the complexities of metabolism and genetics that are not so easy to tackle. However, just having the knowledge that everyone functions differently can broaden your perspective regarding your path to weight loss.
TREATMENT OF DISEASES
The same principle is followed here as well. Some medicines work better for some people than they do for others. Similarly, some medicines have more severe adverse effects on some people while others hardly suffer. A common example is the anti-TB drug Isoniazid which can cause severe side effects in people who are slow-acetylators i.e. they cannot metabolize the drug fast enough.
DOES BLOOD TYPE MATTER?
It had been postulated that our blood types can determine the right diets for us. The idea was that certain food products are better suited for people with certain blood types because they differ in the way they metabolize that food. This idea, however, has since been debunked by researchers from the University of Toronto who have stated that blood type has absolutely nothing to do with our diets and nutritional needs.⁹
AT THE LEVEL OF IMMUNE FUNCTION
The ways in which we differ from each other regarding the functionality of our immune systems are too many to list. Many of these differences arise as a result of different genetics and changes in the environment.
Some people, for example, have a higher likelihood of acquiring autoimmune diseases because of certain alleles of the HLA gene that they harbor.¹⁰ Similarly, some people can acquire allergies because of continuous exposure to an environmental allergen, while others would not be bothered by that allergen one bit.
Interestingly, such differences in immune functionality have also been observed between men and women. It turns out women have stronger immune systems compared to men and therefore are less likely to develop cancer. The reason? The extra X chromosome¹¹. It may also be of interest to know that women are much more likely to acquire certain autoimmune diseases precisely because their immune systems are stronger.¹² A double-edged sword right?
Of note is the hygiene hypothesis that indicates that exposure to certain infectious diseases in early childhood can protect you from more severe diseases later on in life. This concept, when extrapolated to include entire populations and countries, brings to light the different disease trends we see in different parts of the world.¹³
This idea of uniqueness in immune function across individuals and populations strengthens the belief in a personalized approach to healthcare and well-being.
SUMMING IT UP
It should be clear from the discussion above that many seemingly insignificant differences in our genetic makeup and environments can have potentially significant impacts on the way our bodies function. Therefore, it is necessary to be aware of the cocktail of traits each of us possesses to have a more holistic and personalized outlook on our wellbeing. This is one of the principles that we strongly hold onto here at LiveYounger!
We believe in living a youthful and happy life to find meaning in our existence and fulfilling it to the best of our abilities. For us, therefore, the health of the body and the soul is an end in itself! To find out more about the goals we believe in, read my book “Lead A Horse To Water.”¹⁴
Bibliography
- C. Trimmer et al., “Genetic variation across the human olfactory receptor repertoire alters odor perception,” Proc. Natl. Acad. Sci. U. S. A., vol. 116, no. 19, pp. 9475–9480, May 2019, DOI: 10.1073/PNAS.1804106115.
- T. F. Malik and K. K. Panuganti, “Lactose Intolerance,” StatPearls, Jul. 2021, Accessed: Feb. 05, 2022. [Online]. Available: https://www.ncbi.nlm.nih.gov/books/NBK532285/.
- A. C. Poole et al., “Human Salivary Amylase Gene Copy Number Impacts Oral and Gut Microbiomes,” Cell Host Microbe, vol. 25, no. 4, pp. 553-564.e7, Apr. 2019, DOI: 10.1016/J.CHOM.2019.03.001.
- M. K. Andersen et al., “Loss of Sucrase-Isomaltase Function Increases Acetate Levels and Improves Metabolic Health in Greenlandic Cohorts,” Gastroenterology, Dec. 2021, DOI: 10.1053/J.GASTRO.2021.12.236.
- N. Pirastu et al., “Genetics of Food Preferences: A First View from Silk Road Populations,” J. Food Sci., vol. 77, no. 12, pp. S413–S418, Dec. 2012, DOI: 10.1111/J.1750-3841.2012.02852.X.
- K. Mustalahti et al., “The prevalence of celiac disease in Europe: results of a centralized, international mass screening project,” Ann. Med., vol. 42, no. 8, pp. 587–595, Dec. 2010, DOI: 10.3109/07853890.2010.505931.
- B. M. Herrera and C. M. Lindgren, “The genetics of obesity,” Curr. Diab. Rep., vol. 10, no. 6, pp. 498–505, Dec. 2010, DOI: 10.1007/S11892-010-0153-Z.
- M. F. Hjorth et al., “Pre-treatment microbial Prevotella-to-Bacteroides ratio, determines body fat loss success during a 6-month randomized controlled diet intervention,” Int. J. Obes., vol. 42, no. 3, pp. 580–583, Mar. 2018, DOI: 10.1038/IJO.2017.220.
- J. Wang, B. García-Bailo, D. E. Nielsen, and A. El-Sohemy, “ABO genotype, ‘Blood-Type’ diet and cardiometabolic risk factors,” PLoS One, vol. 9, no. 1, Jan. 2014, DOI: 10.1371/JOURNAL.PONE.0084749.
- S. Y. Choo, “The HLA system: genetics, immunology, clinical testing, and clinical implications,” Yonsei Med. J., vol. 48, no. 1, pp. 11–23, Feb. 2007, DOI: 10.3349/YMJ.2007.48.1.11.
- “Women have stronger immune systems than men — and it’s all down to X-chromosome related microRNA — ScienceDaily.” https://www.sciencedaily.com/releases/2011/09/110927192352.htm (accessed Feb. 05, 2022).
- F. Angum, T. Khan, J. Kaler, L. Siddiqui, and A. Hussain, “The Prevalence of Autoimmune Disorders in Women: A Narrative Review,” Cureus, vol. 12, no. 5, May 2020, DOI: 10.7759/CUREUS.8094.
- J. W. Frew, “The hygiene hypothesis, old friends, and new genes,” Front. Immunol., vol. 10, no. MAR, p. 388, 2019, doi: 10.3389/FIMMU.2019.00388/BIBTEX.
- N.Sakr, “Lead A Horse To Water”.