Overweight Parents, Overweight Children

Seems like I’m stating the obvious, doesn’t it? Of course parents have a huge impact on whether their children become overweight. They buy whatever food is in the home and model eating habits. These preferences, however, are most likely partly genetic and partly behavioral.In David Kessler’s new book, The End of Overeating, he discusses how serotonin and dopamine work to increase our cravings and appetite. Both genes and conditioning contribute to the levels of these neurotransmitters in our brain.The interaction between genes and behavior is difficult to tease apart. A recent study has found that the behaviors of obese parents may be more to blame than the genes they’ve passed on to their children.The EarlyBird Diabetes Study looked at 226 British families and found that :Obese mothers are 10 times more likely to have obese daughtersObese fathers are 6 times more likely to have obese sonsThere is no association between obese mothers and obese sons, obese fathers and obese daughtersThe Study’s Director, Professor Terry Wilkin said:Any genetic link between obese parents and their children would be indiscriminate of gender. The clearly defined gender-assortative pattern which our research has uncovered is an exciting one because it points towards behavioural factors at work in childhood obesity.But don’t count out genetics! What about imprinting? Genomic imprinting results in exactly this sort of pattern in which genes are expressed differently depending on the parent of origin, mother or father.Regardless, there is no question that obesity rates in developed countries have increased tremendously. In The End of of Overeating, Dr. Kessler makes the case that it’s because the food industry knows exactly how to alter food chemistry and layer fat, sugar, and salt to make food super-palatable. So even though our genes may not have changed that much in the last half century, the foods that we have ready access to certainly have. Just think what life must have been like before McDonald’s was founded in 1940!In our family the pattern observed in the study seems to be holding true. My son takes after his svelte father while my daughter tends towards the chubbier side. Considering I am feeding them all, I suggest that genes and how they influence what and how much we eat are still important. That doesn’t excuse my tendency to indulge, though. As with everything to do with parenting, time to reconsider what kind of example I’m setting for my kids.News.com.au, ScienceDaily

Which genetic tests make the grade decent?

Tests for diseases with a proven link to single genes. Unlike SNPs tests, which look at gene variations that may put you at higher risk for diseases, some tests screen for specific gene mutations that have been scientifically proven to either definitively cause a disease or greatly increase your chance of developing one. Some disorders that can be screened for this way include breast cancer, colon cancer, Huntington's (a neurological disorder), and hemochromatosis (when the body stores too much iron). When people concerned about these diseases are trying to protect their privacy, some opt to use at-home versions of tests so the results won't be part of medical records. Companies that offer this type of testing include DNA Direct, Kimball Genetics, and Myriad Genetics.

Consider with caution SNPs tests from companies that use a laboratory certified by CLIA, which sets standards for US clinical laboratories. This accreditation ensures that the company uses laboratories that adhere to standards and guidelines for clinical testing. Companies using CLIA-certified labs include DNA Direct, deCODEme, and Navigenics.

Companies that offer genetic counseling. Some genetic tests deal with statistical risk that can be tough to understand and needs to be considered with your family history, so be sure a knowledgeable health professional interprets your test to avoid needless anxiety and any rash medical decisions. Some companies include free online or telephone sessions with certified genetic counselors and send detailed reports to help explain what test results really mean.

Avoid "Nutrigenomic" tests that promise to identify your risk of certain diseases and then sell you expensive vitamin regimes that are supposedly based on your genetic profile and help you prevent disease. The General Accounting Office, the investigative arm of Congress, looked at a number of these companies and found that some of these recommended supplements cost $1,200 a year and were actually similar to supplements found in stores for $35. In some cases, the vitamins exceeded recommended daily allowances, making them potentially harmful, and regardless of the different DNA sample, the "personalized"supplements sent were all the same. GAO investigators couldn't verify any of the scientific claims made by manufacturers of these tests.

Tests from companies without strict privacy policies. Despite last year's passage of the Genetic Information Nondiscrimination Act, which prohibits your insurance company and employer from using your genetic information against you, no laws yet exist to limit what genetic testing companies can and cannot do with a person's genetic information or DNA sample. Be sure that a company securely stores your DNA sample and will not sell it to be used in a research study without your permission. If the company doesn't provide this information on its Web site, ask for it directly. "Using your information without your consent is unethical," says Caroline Lieber, director of the graduate program in human genetics at Sarah Lawrence College.

Tests that don't provide documented scientific evidence validating their claims. You should be fully informed about what a test can and cannot say about your health. Companies should make scientific references available on their Web sites to document the data used for the tests. If they don't offer it, ask for it.

Even if you have one of the 18 genes linked to diabetes, it's not as if it's hardwired into your DNA that you'll get the disease on your 40th birthday--or even at all 

Gene Tests and Gene-Diet Interaction

You've personalized your ring tones, your screensaver on your laptop, and your stationary. You will soon be able to add your diet to that list of customizable items. However, the process won't be quite as quick or simple as a 10-second download, but the promised benefits should be well worth the extra effort.

Genes and health

You probably have at least a basic understanding of genes, those sequences of DNA that control every structure and process in your body. While the basic set of genes that control one characteristic (say eye color) are organized the same for everyone, little differences in the DNA sequence give one person brown eyes and another blue. Likewise, the genes that control how you utilize a certain vitamin, or metabolize cholesterol level, can vary from one person to the next. Now many of these differences can be measured by simple genetic tests, and the results can be turned into personalized diet and nutrition recommendations.

Nutrigenetics

This new science, called nutrigenetics, studies how genes and diet interact. The key word here is "interact." As Rosalynn Gill-Garrison of Sciona, a company that develops genetic tests, points out: "Genes don't determine your fate." Rather these tests give you the information to make optimal choices for your health. A genetic test for bone health, for example, might indicate that you should consume more calcium and vitamin D, rather than saying that your bones are doomed to dissolve.

Currently several companies are developing consumer-friendly tests for known gene-diet interactions. You can be tested for genetic variations that affect bone health, B-vitaminmetabolism, inflammation status, and utilization of certain antioxidants. The tests are typically done on a swab taken from inside your cheek. The sample is sent to a specialized lab, which analyzes DNA from the cells on the swab. You receive a report on which gene variations you have. A qualified health professional can explain the test results, and make specific diet andsupplement recommendations to optimize your health.

What about genetic testing for weight loss?

The $64,000 question is this: When will a genetic test help me to lose weight? Unfortunately, this test does not yet exist. In fact, it is unlikely that just one test will ever answer that question. Registered dietitians Ruth DeBusk and Yael Joffe, co-authors of "It's Not Just Your Genes,"write that genes may someday tell us which weight-loss diet is best, why one person burns more calories than another, and (even better) how to use gene technology to promote weight loss. But they caution that hundreds of genes could impact weight. Deciding which of those hundreds are worth studying will be a daunting task.

The future of personalized diets

Diet and nutrition advice in the future will be increasingly personalized. As genetic researchers identify more gene-diet interactions, dozens of personalized recommendations for diet will be possible. Hopefully, before too long, weight control will also be part of that mix of genetic tests. In the meantime, the first generation of nutrigenetic tests is available for several important diet-gene interactions. One-size-fits-all diet advice will be a thing of the past.

By Donna Feldman, MS, RD

Diet Advice From DNA

Internet marketers claim that a genetic test can give you a personalized diet. Are they advertising cutting-edge science or a high-tech horoscope?By Laura Hercher   When President Bill Clinton stood in the East Room of the White House on June 26, 2000, and hailed the completion of the Human Genome Project, calling its results “the most important, most wondrous map ever produced by humankind,” he was not looking to inaugurate an era of high-tech snake oil sales. Yet less than a decade later Web-based purveyors of genetic tests and dietary supplements are hawking nutritional genetics, or nutrigenetics, with claims that it can look at an individual’s genetic information to figure out what that person should eat to promote stronger bones, shinier hair and other trappings of good health. So far, though, hyperbole has outpaced promise. This nascent field provides a cautionary tale of how commerce often races ahead of science: the commercialization of gene detection technology has occurred before scientists have developed an adequate understanding of how particular genes contribute to health and disease.Information derived from sequencing the DNA code in every human chromosome is gradually enabling scientists to create tests and treatments that have the potential to prevent, diagnose, ameliorate and perhaps even cure disease. It is also paving the way for “personalized medicine,” which is based on the recognition that genetic differences among individuals can explain why one person’s body reacts differently than another’s to food, drugs, sun, exercise, allergens or other stimuli. In an ideal world, a genetic test would reveal which medication or other therapy would work best and produce the fewest side effects in a given individual. And investigators are now beginning to create such tests. One milestone occurred this past summer, when the Food and Drug Administration approved the first genetic test to help a patient gauge the best dosage for a blood-thinning drug called warfarin. The test is certain to be followed by scores of others that attempt to better match drug to patient.