{"id":4921,"date":"2024-01-30T07:00:15","date_gmt":"2024-01-30T12:00:15","guid":{"rendered":"https:\/\/www.chaneyhealth.com\/healthtips\/?p=4921"},"modified":"2024-01-26T21:21:07","modified_gmt":"2024-01-27T02:21:07","slug":"what-can-twins-tell-us-about-diet","status":"publish","type":"post","link":"https:\/\/www.chaneyhealth.com\/healthtips\/what-can-twins-tell-us-about-diet\/","title":{"rendered":"What Can Twins Tell Us About Diet?"},"content":{"rendered":"

What Are The Pros And Cons Of Twin Studies?<\/strong>\u00a0<\/strong><\/span><\/h2>\n

Author: Dr. Stephen Chaney<\/strong>\u00a0<\/strong><\/p>\n

\"\"<\/a>Why is the advice on healthy diets so confusing? One blog claims the vegan diet is best. Another says it is the keto diet is best. The Mediterranean diet is popular, but other experts claim the DASH or MIND diet might be better. Blogs champion diets ranging from the familiar to downright weird.<\/p>\n

If you try to keep up with the science, it seems like the science is constantly changing. Each week you see headlines saying the latest study shows diet \u201cX\u201d is best \u2013 and \u201cX\u201d keeps changing. Why is that? Why do studies on healthy diets keep coming up with conflicting conclusions?<\/p>\n

I have discussed the strengths and weaknesses of clinical studies and why they provide conflicting results in detail in previous issues of \u201cHealth Tips From the Professor\u201d. However, one factor I have not discussed in detail is the effect of genetics on how we utilize foods, something called nutrigenomics.<\/p>\n

Simply put, we are all genetically different. The way we utilize foods is different. The effect that foods have on our bodies is different. I have touched on that briefly in a previous article<\/span><\/strong><\/a> discussing individual difference in blood sugar response to various foods. But that is just one of many examples.<\/p>\n

We do not yet know enough about gene-nutrient interactions to use genomic data to accurately predict which diets are best. Again, I have covered that topic<\/span><\/strong><\/a> in a previous issue of \u201cHealth Tips From the Professor\u201d. However, we do know that genetic differences have a big influence on which diet is best for us. And most clinical studies on diets do not even attempt to take genetic differences into account.<\/p>\n

That is where twin studies come in. Identical twins (monozygotic twins) have an identical genetic makeup and usually have an identical environment until they become adults. So, when I saw an identical twin study (MJ Landry et al, JAMA Network Open, 6(11):e2344457, 2023<\/span><\/a>) comparing a vegan diet (only plant foods) with an omnivorous diet (both animal and plant foods), I wanted to review it and share it with you.<\/p>\n

How Was The Study Done?<\/strong>\u00a0<\/strong><\/span><\/h2>\n

\"Clinical<\/a>Identical twins were recruited from the Stanford Twin Registry. Twenty-two identical twin pairs were chosen for this study. Their characteristics were average age = 40, BMI = 26% (moderately overweight), sex = 77% female, ethnicity = 73% white, followed by an approximately equal representation of Asian, black, multiracial, and Pacific Islander.<\/p>\n

One unanticipated characteristic of this group of twins was that 70% of them still lived together and cooked together, so their environment was also very similar.<\/p>\n

One twin of each pair was put on a healthy vegan diet and the other on a healthy omnivorous diet for 8 weeks. Both diets were designed by dietitians. The diets emphasized fruits, vegetables, and whole grains while limiting added sugars and refined grains.<\/p>\n

Both diets were healthier than the diets the twins were eating prior to the study. Finally, the participants were not told how much to eat, and were not instructed to lose weight.<\/p>\n

For the first four weeks the participants were provided with all their meals by a nationwide food delivery company. The participants were also provided with training on purchasing and preparing healthy foods for their diet. This prepared them for the last 4 weeks of the study in which they purchased and prepared their own meals.<\/p>\n

Participants visited the Stanford Clinical and Translational Science Research Unit at the beginning of the study and at the end of weeks 4 and 8 for weight measurement and a fasting blood draw.<\/p>\n

Adherence to the diets was measured by a series of unannounced interviews to administer a 24-hour dietary recall questionnaire. These were scheduled for the weeks they visited the clinic.<\/p>\n

What Can Twins Tell Us About Diet?<\/strong>\u00a0<\/strong><\/span><\/h2>\n

\"Twins\"<\/a>Even though the sample size was small, there were three statistically significant results.<\/p>\n