A couple of years ago, I submitted my raw 23andMe data to several companies for nutrition and wellness analysis. These companies put out reports that suggest predispositions based on combinations of gene variants. Instead of yielding clear and helpful guidance, it made things much more complicated. The results were often contradictory, unclear, useless, or verifiable by other means.
Sensitivity to Dietary Fat
One company noted that I have a “higher sensitivity to fat” and recommended I get precisely 15% of my calories from polyunsaturated fatty acids and 12% from monounsaturated fatty acids. Food labels don’t separate fat into monounsaturated vs. polyunsaturated fat, and nearly all fats have varying proportions of both, so I’m not sure how they expect consumers to reach this level of precision.
Another company came up with an entirely different conclusion: “You are less sensitive to saturated fats...you can consume more saturated fats-rich foods than average without a high risk of obesity.” This was excellent news to my chocoholic ears. Yet a third company reported “a highly-sensitive cholesterol response to eating dietary fat” and suggested I consume 15% of daily calories from fat. That’s a very different recommendation than the first one suggesting 15% of fat just from polyunsaturated fat!
Carbohydrate Sensitivity
Two out of three companies suggested a “high sensitivity” to carbohydrates and to aim for a daily glycemic load of 70. Who calculates daily glycemic load?? It’s impractical and nearly impossible to tabulate and track. Furthermore, our response to carbohydrates very much depends on the type of carbohydrate (are we talking about jelly beans or kale) as well as the type and quantity of fat and protein consumed.
Vitamin Requirements
According to one company, I have a “raised” vitamin D requirement, to at least 800 IU daily. A second company says I’m “less likely to have lower blood levels of vitamin D due to increased ability to transport vitamin D in the body.” My own personal experiment suggests the former, but this sort of data is probably best monitored by a routine blood test and not a genetic prediction. Furthermore, many of these companies also sell their own supplements after making personalized supplement recommendations to consumers!!
Extraneous Information
23andMe suggests I’m likely to wake up at 8:23 AM. Interesting, but completely useless and inaccurate. I have not slept past 8 for approximately 10 years. Many companies also report on caffeine sensitivity, but I’ve yet to meet a client or friend who is unaware as to the effects of caffeine on their bodies. They all know without a test whether they become jittery after a sip of Starbucks or whether they can enjoy an after-dinner cappuccino.
Bottom line: Don’t waste your money just yet. Perhaps these companies have improved their predictive abilities since I submitted my raw data to them a while back but I don’t think these reports should be used by dietitians or other health care providers for all the reasons listed above. Much of the “individualized” advice provided was extremely basic nutrition information that could be applied to the general population. Trust your own symptoms and reactions to food, make sure you get lab tests yearly to check things like vitamin D and B12, and aim for a balance of carbs, fat, and protein from whole plant foods on a daily basis.
Additional Reading and Sources