One of the most exciting areas of nutrition research is into nutrigenomics, or the way that genetics impacts nutrition. Based on evidence that tailoring drug therapies to a person’s genetic profile, personalized genetic nutrition may be a tonic for lowering disease and obesity.
How Does It Work?
People have genetic differences, which are known as single nucleotide polymorphisms (SNPs) that occur through a person’s DNA. Each SNP represents a difference in a single DNA building block, called a nucleotide. Emerging research shows that distinct SNPs predict how a person will respond to certain foods and drugs. SNPs also impact our susceptibility to environmental toxins, such as allergens, and risk of developing certain diseases.
Recent research shows the potential of nutrigenomics:
Personalize Your Carb Intake
There is wide variability in how much people’s blood sugar spikes after meals. In the past, researchers have attributed these differences to different levels of physical activity, body fat percentages, and composition of the gut microbiome, among other factors. New research shows that genetics impact blood sugar regulation and insulin sensitivity as well. For example, in one study, people with genetic SNPs who had a higher carbohydrate intake experienced a significant increase of fasting insulin and HOMA IR test.
Some studies show that a lower carbohydrate diet is one solution for people with SNPs that are linked to higher blood sugar spikes and insulin resistance. For example, one trial found that in women with greater insulin resistance, a low-carb diet resulted in much greater loss of body fat compared to women who were classified as insulin sensitive. In the women who were insulin sensitive, a low-fat and low-carb diet were equally effective for inducing fat loss.
Adjust Your Protein & Fat Intake
Naturally, if how your body processes carbohydrates is impacted by genetics, protein and fat are also likely to be. Recent studies show that people with specific variations of the FTO gene respond better to diets higher in protein (20-30 percent of calories) than those on low-protein diets. Researchers think that protein results in a decrease in appetite and cravings that can translate into an energy deficit for successful fat loss.
Another genetic variant has been associated with greater risk of obesity when a high-fat diet is consumed. Other people respond well to a higher proportion of calories from dietary fat. One theory is that people with the obesity—high fat variant who increase their physical activity may lower their risk of obesity.
Individualize Your Coffee Intake
The ability to metabolize caffeine varies widely based on genetics. Some people are fast metabolizers, others are slow, and this response determines both how they will respond to caffeine and how they can benefit from coffee. For example, studies suggest there are anti-inflammatory and anti-diabetic effects of coffee, however, certain polymorphisms, or genetic varieties make people more sensitive to caffeine.
This may be a two-edged sword: In some people, even a small dose of caffeine may make them jittery or anxious. When applied in an athletic performance setting, it may pay off in greater athletic performance. Caffeine is a well known athletic performance enhancer and a study of athletes found that people with a genetic variation called CYP1A2 had a significant increase in performance compared to those without the polymorphism.
Personalize Sodium & Saturated Fat
Research shows that how our bodies respond to sodium and saturated fat is unique and related to our genes. For example, there is a genetic phenotype of the ACE gene that is associated with sodium sensitivity that increases risk of elevated blood pressure from a high sodium intake. Although, for the population in general a low sodium intake has been identified as largely useless for controlling blood pressure and may be harmful, it may be appropriate for people with a sodium sensitivity.
Something similar has been observed with a high fat diet and cholesterol: In the majority of the population, cholesterol levels are autoregulated by the liver, but, in people with a certain genetic SNP of the APOE gene, a diet high in saturated fat will raise cholesterol levels and may increase risk of cardiovascular disease. In a minority with another variation of this gene, lowering saturated fat intake can have a harmful effect.
Interestingly, certain SNPs of the APOE gene also eliminate the protective effect of red wine on cardiovascular disease. In one review, scientists recommend that people with this genotype need to be rigorously attentive to diet and lifestyle, avoiding smoking, alcohol, and optimizing fat intake by prioritizing monounsaturated fat and de-emphasizing saturated fat.
Genes Aren’t Destiny
Scientists recommend that everyone avoid sugar-sweetened beverages including soda, juice, and energy drinks. But for people with certain “obesity genes,” sugar sweetened beverages are a disaster waiting to happen. People with these genetic variations are more susceptible to increased body fat from drinking sugar-sweetened beverages than those with fewer obesity genes. The study in question also suggested that regular sugary beverage consumption may actually amplify the genetic risk of obesity. Choosing healthy lifestyle factors has the opposite effect: Avoiding sugar sweetened beverages, eating more fruits and vegetables, and increasing physical activity can all mitigate the genetic risk of obesity even in those with “obesity genes.”
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