Author: Lisa Drayer, CNN
(CNN) – Most of us know that we need to eat more whole grains, vegetables, and cereals.
So why would the National Institutes of Health spend $ 150 million to answer questions like “What and when should we eat”? and “How can we improve the use of food as a medicine?”
The answer may be precision nutrition, which aims to understand the health implications of the complex interaction between genetics, our microbiome (bacteria that live in our intestines), our level of diet and physical activity, and other social and behavioral traits.
This means that everyone can have their own unique set of nutritional requirements.
How is that possible? I asked three experts in specific nutrition research: Dr. Frank Hu, a professor of nutrition and epidemiology and chair of the Department of Nutrition at Harvard TH Chan School of Public Health, and Martha Field and Angela Poole, both assistant professors in the division. Cornell University’s Faculty of Human Ecology in Nutritional Sciences.
Below is an edited version of our interview.
CNN: How different is precision nutrition from current nutrition advice?
Dr. Frank Hu: The idea of precision nutrition is to have the right foods, in the right amount, for the right person. Instead of giving general dietary recommendations to everyone, this precision approach adapts nutritional recommendations to individual characteristics, including one’s genetic background, microbiome, social and environmental factors, and so on. This can help you achieve better health outcomes.
CNN: Why isn’t there a one-size-fits-all recipe for what we need to eat?
He: Not everyone responds in the same way to the same diet. For example, given the same weight loss diet, some people may lose a lot of weight; other people may gain weight. A recent study at JAMA put hundreds of overweight people at random on a healthy low-carb, low-fat diet. Within a year, the weight loss was almost the same for both groups, but there was a big variation between the people in each group: some lost 20 pounds. Others gained 10 pounds.
Martha Field: Individuals have special responses to their diet, and the “fine-tuning” of precision nutrition is to understand those responses. This means understanding the interactions between genetics, individual differences in metabolism, and exercise responses.
CNN: How do we eat accurately based on nutrition principles now?
He: There are some examples of personalized diets to manage disease, such as a gluten-free diet or a lactose-free diet to manage celiac disease if you are intolerant to lactose. People with a condition known as PKU (phenylketonuria) should consume a diet free of phenylalanine. It’s a rare condition, but a classic example of how your genes can affect what type of diet you should consume.
Angela Poole: If I had a family history of high cholesterol, diabetes, or colon cancer, I would increase my consumption of dietary fiber by eating many different sources, including different vegetables.
Zone: If you have high blood pressure, you should be more aware of your sodium intake. Anyone with poor absorption may need higher levels of micronutrients, such as B vitamins and some minerals.
CNN: There are studies that show that people metabolize coffee differently. What are the implications here?
He: Some people carry fast genes to metabolize caffeine; others carry slow genes. If you carry fast (metabolizing) genotypes, you can drink a lot of caffeinated coffee because caffeine decomposes quickly. If you are a slow metabolizer, you get nervous and if you drink coffee in the evening you will not be able to sleep. If so, you can drink decaffeinated coffee and get the benefits of coffee polyphenols, which reduce the risk of heart disease and diabetes without the effects of caffeine.
CNN: How important is our individual gene at risk for disease? And can our behavior reduce our risk of illness?
He: Our health is affected by genes and diets, which are constantly interacting with each other because certain dietary factors can activate or deactivate certain disease-related genes. We have published research showing that reducing the consumption of sugary drinks can offset the negative effects of obesity genes. This is really good news. Our genes are not our destiny.
Another area of precision nutrition is the measurement of blood or urinary metabolites, the small molecules that are formed when food is broken down and ingested. For example, having a higher concentration of branched-chain amino acids (BCAAs) strongly predicts the risk of future diabetes and cardiovascular disease. Blood levels of BCAAs depend on a person’s diet, gene, and intestinal microbiome. We found that eating a healthy diet can alleviate the harmful effects of BCAAs on cardiovascular disease. Therefore, measuring BCAAs in the blood can help assess the risk of developing diabetes and cardiovascular disease and encourage dietary changes that reduce the risk of chronic disease.
Zone: Environmental effects can sometimes be of the same magnitude as the genetic effects of the risk of disease.
CNN: Our individual microbiome can decide what kind of diet we should consume. Can you tell us about this emerging research? And what do you think about microbiome testing?
Poole: Research has shown that in some people, blood sugar is higher for eating bananas than for eating cookies, and has been linked to the composition of the microbiome. Scientists have used microbiome data to build algorithms that can predict an individual’s glucose response, and this is a breakthrough. But that’s not an excuse for me to throw bananas instead of bananas. Also, because of the blood glucose responses, if the algorithm suggests eating white bread instead of whole wheat bread, I wouldn’t eat only white bread all the time.
At the moment, I’m not ready to spend a lot of money to see what’s in my gut microbiome … and the microbiome changes over time.
He: Microbiome testing is not cheap, and it promises to help you develop a personalized meal plan that can improve your blood sugar and blood cholesterol … at the moment, the data is not crucial.
CNN: How will the nutrition advice differ 10 years from now?
Poole: I think you’ll get a tailor-made list of foods in one app: the foods you want to buy and the foods you want to avoid, based on your blood sugar responses, your level of physical activity, and more.
He: We will have more and better biomarkers and cheaper and more accurate nutrigenomics and microbiome testing, as well as better computer algorithms that predict your response to food consumption.
But these technologies cannot replace general nutritional principles, such as limiting sodium and added sugar and eating healthier plant foods. In a few years, you may be able to get a more useful answer from Alex if you ask him what to eat, but like other answers from Alex, you will need to take him with a grain of salt.
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