Do your genes hold the answer?

Nutrigenomics studies how food can interact with your genetic make-up to tip the balance between health and disease

An improper diet is a risk factor for a number of diseases. However, the exact effect of different components of food may depend on a person’s genetic make-up. Nutritional genomics or nutri-genomics is the study of how different foods can interact with particular genes to alter a person’s risk of developing diseases such as Type 2 diabetes, obesity, heart disease and cancers and how individual genetic differences can affect the way we respond to nutrients in the foods we eat. It is not a question of whether your genes are good or bad, but rather how they interact with your environment.

The science of nutrigenomics also studies how genes, diet and disease interact to make people from different races more vulnerable to a particular disease. For example, African-American men have a 60 per cent higher risk of being diagnosed with prostate cancer than do Caucasian men. Half of all adult Pima Indians in the United States have Type 2 diabetes, compared with 6.5 per cent of adult Americans of Caucasian descent. A single letter change in DNA in people from Scandinavia 10, 000 years ago allows most Caucasian adults today to drink cow’s milk without getting sick due to lactose intolerance. Genetics, diet, economic, environmental and social conditions, culture and behaviour may all contribute to these differences.

So far, modern nutrition and medicine have not worked on designing diets or medicines according to different ethnic groups or body types. Scientific wisdom is based on the premise that what works for one should work for most. It does not factor in individual differences. A study becomes valid only when results apply to most or the statistical difference is significant. On the contrary, alternate or traditional systems have believed that individuals are different and have categorised people into different types. Traditional therapies like Chinese medicine, Unani, Ayurveda and homeopathy are based on this premise. This could probably be an explanation of why one of the largest scientific trials on homeopathy failed to prove its efficacy. Nutrigenomics seems to be integrating this gap, studying genetic profiles and customizing nutrients and foods according to the DNA.

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The nutrigenomics effort seeks to identify genes controlled by nutrients and other naturally occurring chemicals in food and to study how some of these genes can tip the balance between health and disease.
Nutrients may alter disease initiation, development, or progression. Individual genetic variations can influence how nutrients are assimilated, metabolised, stored and excreted by the body. Nutritional genomics claims individuals can manage their health and well-being better by precisely matching their diets to their unique genetic make-up. In the US, there are claims you can make your children more intelligent by customising their diet according to their genetic make-up…. There is also the DNA diet, which claims you can lose weight, tone up and even live longer by following advice based on an analysis of your DNA.

So far, evidence on the interaction of nutrients, genetic variations and health implications is uncertain and controversial. In fact, according to US Government Accountability Office, nutrigenetic tests “may mislead consumers by promising results they cannot deliver” and issue medical predictions that may either needlessly alarm or in some cases, falsely assure, consumers about their health. There is also a hefty price associated with these genetic tests.

Interactions between multiple genes, nutritional and other environmental factors are so complex that there is no validated evidence to support this sort of approach. It is a relatively new field. There is still not enough information available as to how food truly interacts with genes. However, companies are already marketing technology to dieters to lose weight or rectify health problems. Can the new science of nutrigenomics provide solutions by altering the expression of genes? At best, it is premature and seems to be oversimplifying complex “nature versus nurture” issues.
However, this may well be the road ahead for personalised dietary intervention based on knowledge of nutritional needs, nutritional status and genes to prevent, mitigate or cure chronic diseases.