NEW YORK (AP) – Avoid fast food, eat vegetables and do not exercise. It sounds like a general health advice, but it's supposedly tailored to my DNA profile.
The suggestions come from 23andme, one of the companies that points out the optimal eating and exercise habits of your genetics. As with most diets, the idea is appealing because it has an elusive reason why you can not get in shape – in this case, your genes.
But Isaac Kohane, a biomedical researcher at Harvard, said in the study The field is still limited and there is little evidence that small effects of genetic variation can be translated into meaningful nutritional recommendations.
"By and large, these factors are not very valuable to the people who buy them," he added. In addition, other factors play a much bigger role in health, such as how much we eat.
Still, it's tempting to think that your DNA contains clues to your ideal diet. To find out what my genes could show, I tried two services, 23andMe and DNAFit.
If you pay $ 99 for a 23-month-old history report, you can spend $ 1
The extras you receive include various wellness reports, including a report that predicts your "genetic weight" and provides more insights into your diet. These results are based on comparisons with data from other 23andMe customers.
After adjusting the standard setting from European to East Asian descent, I said in my report that I am inclined to weigh "above average". For a 40-year-old 5-foot-6 woman, the company defined an average of 138 pounds. 23andMe notes that most of its clients are of European descent and that the data is limited to other ethnic groups.
The report then lists 10 habits associated with healthy weights for your DNA profile. For me this included restricting red meat, avoiding fast food, and training at least twice a week. Given how formulaic that sounded, I wondered how many results differ for others.
It turns out that everyone has the same 10 habits as these are the ones who decided to interview people. However, the order in which they appear varies to indicate the magnitude of their suspected effect for you. Alisa Lehman, senior product scientist for 23andMe, said the top two habits for most people limit red meat and avoid fast food as they were for me.
Like many other nutritional studies, the results prove no cause and relationships between the genes of the customers and the survey results make connections.
Other wellness reports said I am more likely to be lactose intolerant (check), to purge alcohol (check), and to consume less caffeine (check). They were more interesting because of their particularity, but did not reveal anything surprising. Another report said that my weight is not likely to be affected by my intake of saturated fat, which is common in meat.
The only surprise was that I have a genetic variant that "is common in elite competitive athletes." However, I've seen from the link that about half of the customers had the same variation.
For $ 99.99 you get a saliva collection that reports on various fitness and nutritional traits. If your DNA file already has 23andMe, you can upload it to get instant results for $ 79.
DNAFit says its reports are based on a broader universe of scientific research on genes and nutrition.
Given the general fear of carbohydrates among many dieticians, I started with the "carbohydrate sensitivity" report. It started with a review that explains the difference between complex carbohydrates like brown rice and refined carbohydrates like sugar that are digested faster.
After scrolling down, the report said that I have a "very low" sensitivity, meaning that I am less susceptible than others to sugar highs and diabetes. Despite this tolerance for carbohydrates, it has been suggested to limit the carbohydrates to ten percent of the daily calories. Again, it sounded like a general piece of advice and made me ask to what extent the recommendations vary for others.
Andrew Steele, Product Manager at DNAFit, said that the recommended limit for refined carbohydrates is between 6 and 10 percent of total calories. For someone who consumes 2,500 calories daily, that ranges from 150 to 250 calories.
While this does not seem to make much of a difference, reducing DNAFit from 10 to 6 percent means a 40 percent reduction. However, the relatively narrow range underlines the notion that nutritional counseling is largely consistent regardless of your genes.
Another report said that my sensitivity to saturated fat was low, and suggested limiting it to 10 percent of calories. DNAFit said the range for this recommendation is also 6 to 10 percent.
Other reports were more nutrient-specific. One said I have an increased need for omega-3, the cholesterol-lowering fatty acid. Another said I have an increased risk of DNA damage from grilled meat and should limit it. (This note was given about a candlelit candle image.)
On the fitness side, the reports say I'm more prone to endurance activity than high-intensity activity. I do not know if I'll take this into account when I start training. Others have questioned the accuracy of fitness reports in which the aerobic potential of an Olympic runner was considered "moderate".
DNAFit and 23andMe say that knowing your genetic predisposition can motivate you to stick to diet or exercise routines. You may also have specific reasons why you want to try the services, especially 23andMe, which have the most for the lineage tests and many other reports. For me, however, the results felt too broad to influence my habits.
Just a note: DNAFit is based in the UK. So, if you decide to give it a try, there might be a small change fee on your credit card statement.
Follow Candice Choi at www.twitter.com/candicechoi
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