A Perfect Diet is in Your Genes
The search for the perfect diet has long been the pursuit of those searching for optimal health, maximum energy, and physical appearance. We know that each of us is different and that while beauty may be ‘in the eye of the beholder’, health and fitness is something we can measure. And to that end, many of us are still searching for the proverbial “magic bullet” that guarantees optimal health, vitality, and appearance.
As a Professor of Human Nutrition at the University of California, San Diego I try to impress upon my students that diet is not determined by a single meal or a single food, it is the product of all the choices we make, including the foods and liquids we put in our body, our physical activity, and our mental toughness. To that end I like to begin my first lecture with two thoughts:
#1 — Nutrition is a known science defined by six nutrient classes: carbohydrates, proteins, lipids/fats, vitamins, minerals, and water.
#2 — There are no “good” foods or “bad” foods, only good choices and bad choices.
The Science of Nutrition
In nutrition, diet is the sum of the foods consumed by a person or other organism. The word diet often implies the use of specific intake of nutrition for health or weight management reasons, with the two often being related. Complete nutrition requires the ingestion and absorption of macromolecules, or energy containing foods in the form of carbohydrates, proteins and fats. In addition an adequate diet requires the intake of the vitamins, minerals and water that do not contain calories. Many nutrients are essential, in that our body cannot synthesis or make them ourselves, they must be ingested either from foods or supplements. These include essential vitamins and minerals, essential amino acids from protein, and essential fatty acids from fat-containing food. Dietary habits and choices play a significant role in the quality of ones life, overall health and longevity.
This may sound like an easy task but the intake of an optimal amount of all nutrients must be balanced with overall caloric utilization, in other words energy or calories in must equal energy or calories out in order to maintain weight.
The Role of Genetics
The foods we eat and our acquired tastes are always changing but our nutritional requirements have been based on our physiology and biochemistry. Today, the science of nutrition has expanded to include our genetics. The nutrients we consume must be digested and absorbed in our gastrointestinal tract and that process may be influenced by our genetic make up.
Wouldn’t it be nice if we each had a unique nutritional blueprint within our genes? This novel industry is just beginning to bloom. Naturopathic doctors will draw blood and run an analysis of your vitamin and mineral content while companies such as Habit, Profile Precise and Nutrigenomix will take a DNA sample to determine if there is a variant of a gene that reflects a sensitivity to foods such as caffeine.
Nutrigene, a start-up company that combines vitamins with DNA analysis, believes your genes may hold the secret to what you might be missing in your diet. Oh, and the company will send you a tailor-made liquid vitamin supplements based on a lifestyle quiz and your DNA! But remember, nutrigenetics is still an early science.
Finding the link between diet and genetics could explain why some individuals are successful on one type of diet while others are not. Unfortunately, in one of the most rigorous studies so far, they found no difference in weight loss between overweight people on diets that “matched” their genotype and those on diets that didn’t. Published in the Journal of the American Medical Association Network in February 2018, the DIETFITS randomized clinical trial found that there was no significant difference in 12-month weight loss between a healthy low-fat diet and a healthy low-carbohydrate diet, and neither genotype pattern nor baseline insulin secretion was associated with the dietary effects on weight loss. In fact, it was reported that genes only explain about 5% to 10% of the risk linked to diet-related diseases such as obesity and type-2 diabetes. The lead researcher of the DIETFITS study stated; “There was no significant difference in weight change among participants matched vs mismatched to their diet assignment, and there was also no DNA/diet interaction for waist circumference, body mass index, or body fat percentage.”
Conclusion
Precision and personalized medicine is clearly here to stay and has resulted in approved therapies for the treatment of a number of cancers including metastatic melanoma and some lymphomas. However, personalized diets remain a thing for the future. Finding an answer to our dietary woes in our genes will take many more years of controlled clinical trials.
Dr Jeffrey Blumberg, a professor of nutrition science and policy at Tufts University in Massachusetts stated that by 2028 “the emerging field of ‘personalized nutrition’ will use genetic tests to fill in those gaps to offer healthy eating guidance tailored to the individual.” This may mean that cooking for the family is going to be a lot more complex!
My view, as a professor of nutrition, is that the marketing of DNA or genetic-based nutritional advice has gotten ahead of the science. However, people are clearly interested in obtaining this new information and there is a value in that people may stop and think about what they are eating, whether they are exercising, and the overall choices they are making to optimize their own personal well-being. This self awareness alone may result in improved overall health.
