What if choosing a diet that's right for you were as easy as a walk to your mailbox? There, you find a small package containing simple instructions and a special cotton swab sealed in a container designed to prevent contamination. You remove the cotton swab, open your mouth and rub the swab across the inside of your cheek. Putting the swab back into its container, you seal it and drop it in a mailbox
A few weeks later, a trip to the mailbox yields another small package, this one filled with your genetic analysis along with a recommended diet tailor-made for you. Perhaps the genetic analysis determined that you're missing a gene that aids the body in using a certain vitamin. Or, you may learn that your liver isn't able to break down certain substances due to another variation in your genes. By adjusting your diet, you optimize your genes' strengths and bolster their weaknesses, leading to a healthier life.
Sound too good to be true? It is (for now), but it's the goal of nutrigenomics. Nutrigenomics, in essence, studies the two-way street connecting genes and nutrition.
Two primary questions drive nutrigenomics: How does nutrition and diet affect our genes, and how do our genes affect the body's response to nutrition and diet?
A customized nutrigenomic diet would reflect your body's specific needs. For instance, some people are more prone to experiencing vitamin deficiency than others. For those whose bodies metabolize vitamins perfectly, there may be no need to consume extra servings (in food or pills) of specific vitamins. Once you know your body's needs, it's easier to fulfill them.
A deeper understanding of your genetic makeup would help, too -- certain ethnic groups react more negatively than others do to Western-style foods and the sedentary lifestyle that often accompanies them, for example. The Inuit have, for thousands of years, relied on a high-fat diet to provide the energy needed to go out and hunt down calories while trudging along frozen terrain. But if you have Inuit ancestors and you're a customer-service rep working in a cubicle in Phoenix, your body's tendency to maximize the storage and use of fat won't do you or your waistline much good, and a nutrigenomic analysis could point this out to you.
Diet isn't only related to the prevention of disease -- it's also instrumental in attaining good health. While you may think these two things are one and the same, the lack of disease doesn't necessarily mean you have good health. It just means you're free of disease, although the situation can change quickly unless you exercise, eat right and stay away from the bad stuff. According to nutrigenomicists, bolstering your body's genetic deficiencies with the right nutritional choices will help you travel a long distance on the road to good health.
Some people are just genetically predisposed to getting certain diseases. Some of the difference may be partly accounted for with lifestyle choices, but certain ethnic groups seem to be more prone to getting diseases like diabetes or heart disease than others. Genes can be directly affected by diet, and the interplay between the two may be responsible for the appearance and advancement of many diseases. By identifying which of your genes are likely to cause you health problems, you may one day be able to neutralize them through your diet and live a longer, healthier life.
Nutrigenomics is a growing (and relatively young) field of study, yet some nutritionists already offer genetic testing of a limited number of genes in hopes of providing you with a way to improve your diet and your health.
Nutritionist Carolyn Katzin has developed the DNA Diet, for which she tests clients for several genes. While this is a good start, it's only a drop in the bucket -- humans have at least 20,000 different genes. The current level of nutrigenomic testing can provide useful dietary health solutions, but the full benefit of this advancement has yet to be realized.
However, Katzin's DNA Diet and testing procedures may yield useful information for individuals. One of the genes that's tested -- glutathione-s-transferase mu -- plays a role in detoxification, and up to half of all Caucasians may be missing this gene.
By bolstering detoxification abilities of the body by adding specific vegetables (such as cabbage) or nutrients to aid the liver, the thinking goes that this will help the body eliminate toxins and waste, resulting in better health.
But attaining better health through nutrigenomics may not be as simple as adjusting for a missing gene here or there. Foods interact with many different genes at once, and not just one specific gene. Additionally, dietary changes may be beneficial to the expression of one gene, but detrimental to the expression of another. Researchers are still learning how food affects the entire spectrum of our genetic makeup, but current genetic testing and dietary manipulation offer a promising start.
As many genes as we have, some are surprisingly important when it comes to dietary interaction.
Researchers have discovered one gene that determines how quickly caffeine can be processed by your body. This decides how much caffeine can be tolerated by the body or how much a person may be likely to drink (especially if caffeine's effects fade quickly). It might not seem too important, but people who don't process caffeine as fast may be at higher risk of heart attack even if they drink less of it, according to Genome BC.
Speaking of heart health, genes make a difference in whether or not you'll improve your cardiovascular health through diet and lifestyle changes alone, or if improvement will require medication. The genetic makeup of some people allows them to eat pretty much whatever they want without raising their cholesterol levels. Other people can eat an extremely "cholesterol-smart" diet and their numbers won't budge at all. Knowing how your genes affect your dietary cholesterol intake will allow you to better tailor your overall approach to fighting high cholesterol -- or allow you to breathe easy and order an extra egg.
Researchers are trying to figure out exactly what foods in what amounts are optimal to prevent such diseases. It's known that calcium intake early in life reduces the risk and the speed of advancement of osteoporosis, but further nutrigenomic research should help us determine who needs calcium the most, and in what amounts.
One basic form of nutrigenomic diet has long been in existence, creating pretty radical changes in diet (albeit by default).
When it comes to gluten intolerance or lactose intolerance, some individuals' genetic makeup prevents their ability to process wheat or dairy products. You don't need a DNA test to find this out, as your body will express its displeasure upon coming into digestive contact with these substances. Food intolerance makes people feel ill when they've chosen the wrong menu item, but many people don't realize the nature of the problem until after consulting with a doctor.
While avoidance of non-tolerated foods solves the problem, supplemental enzymes can also be consumed that allow for the consumption of these products. But do some people develop food intolerances while others don't? The root of the problem is genetics.
We'll take lactose intolerance as an example. Humans -- like animals -- traditionally have lost the tolerance for lactose by the time of adulthood. However, people in Northern Europe about 10,000 years ago developed the ability to continue tolerating lactose through adulthood. Descendents of those Northern Europeans are much more likely to be free of lactose intolerance than other ethnicities. But if your ancestors made their home in Asia, Africa or even southern Europe, that's not a definite indication you won't be able to drink a glass of milk as an adult. Future nutrigenomic testing may be able to determine beforehand if you'll develop a food intolerance, and may even be able to suppress or facilitate the expression of certain genes that can prevent this from happening.
As the study and practice of nutrigenomics advances, it will undoubtedly yield surprising dietary insights and personalized benefits to those who pursue its offerings. And by altering your diet to better suit your genes, your genes may allow your diet to better suit your jeans.
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