30 Dec Genetics playing a growing role in intersection of nutrition and health
Originally published on The Baltimore Sun.
Dr. Erin Kinney used to assess patients nutritional needs with an analysis of their eating habits and family and medical histories. Nowadays the Arnold naturopathic doctor is delving deeper and also analyzing her patients’ genetic makeup.
She is part of a growing number of dieticians, nutritionists and holistic doctors practicing nutritional genetics, or looking at how variations in genes can modify the affects of nutrients on health. The health care providers are using the information to help patients figure out which foods they should eat or avoid, and that best suits their biological makeup.
“We are now learning that maybe you have a certain genetic disposition to not making enough of a certain enzyme,” said Kinney, who is also president of the Maryland Naturopathic Doctors Association. “It is really changing the way we are going to be able to tailor our treatments for patients.”
Dieticians for years have used genetics on a limited basis, looking at mutations in one particular gene that may make patients prone to disease or more likely to have certain health conditions. For example, patients who are lactose intolerant can’t break down the lactose found in dairy products because of a mutation in the lactose gene. So they suffer with gas and other uncomfortable digestive problems after drinking milk or eating cheese or ice cream.
The sequencing of the human genome – or the mapping of every gene in the body – has enabled not just dieticians, but all doctors, to use genetics in a more comprehensive way. A doctor can look at a patient’s entire genetic makeup to determine, for instance, if they have multiple gene mutations that would make them more prone to obesity or cardiovascular disease.
Most human genes are the same from person to person, but some have variations. The most common type of variation is known as a SNP (pronounced “snips”), or single nucleotide polymorphisms, and accounts for difference in physical characteristics of people, including eye and hair color or blood type. Different SNPs can also determine if someone will be more prone to developing certain diseases.
“The genome is the gold mine where genes can be targeted and we can learn more about how nutrients can play a role in people’s health,” said Braxton Mitchell, a genetic epidemiologist at the University of Maryland School of Medicine who studies the genetics of complex diseases.
But Mitchell and others caution the field is still emerging and that ongoing research is needed to sort out the many ways genetics could be used to guide nutrition and food choices.
The Academy of Nutrition and Dietetics wrote a position paper in 2014, published in the organization’s journal, that said nutritional genomics is not ready for widespread use.
“The practical application of nutritional genomics for complex chronic disease is an emerging science and the use of nutrigenetic testing to provide dietary advice is not ready for routine dietetics practice,” the position paper said. “Registered dietitian nutritionists need basic competency in genetics as a foundation for understanding nutritional genomics; proficiency requires advanced knowledge and skills.”
A spokesman for the organization said it still stands behind that statement.
“It is pretty complicated right now because genes are complicated,” said Ginger Hultin, a dietician and spokeswoman for the Academy of Nutrition and Dietetics. “It is not generally enough to just look at a single gene variation. There is so much to look at on genes and you also have to consider a person’s lifestyle and how they interact with the environment.”
The Maryland University of Integrative Health held its first ever symposium last month to encourage what they called “knowledge sharing” on the interaction between genetics and dietary factors. The conference, held in partnership with the Maryland Naturopathic Doctors Association, was focused on giving health care providers practical advice on how to incorporate nutritional genomics testing, counseling and treatment into clinical practice.
Christy Williamson, an adjunct professor at the university who also owns a genetic nutritional company, said that variations in genes might mean that two people with diabetes might need different diets customized for their biological makeup. Other people might have a gene variation that causes them to need more exercise to get enough molecular oxygen to lose weight.
There is also the possibility that a mutation might not have any affect on the body.
“Certain things are epigenetically activated,” Williamson said. “That doesn’t mean everybody who has a gene variation will get that particular disease. Genetics kind of loads the gun and the environment pulls the trigger.”
Lifestyle can also offset the affects of the gene variation. If your gene makes you more prone to gain weight, for instance, extra exercise could help you fend off weight gain.
“You can have bad genes, but if you have a good lifestyle you can change the way your genes are expressed,” Kinney said. “Your body can get back into balance despite that your body has these gene mutations.”
Companies like 23andMe, Vitagene and Nutrigenomix will map a patient’s genome using a swab of saliva. Kinney then uses a system called Opus 23 Pro that analyzes the data.
Kristen Kissik, an Annapolis dance and yoga instructor, was one of those patients who had her genome analyzed. Kissik wanted to make sure she was doing everything she could to ensure she had the most optimal health. She had been eating foods she knew would help reduce inflammation, improve her thyroid functions and ease her gluten sensitivity.
“The stuff I got almost affirmed my intuition,” Kissik said of the results her genome analysis. “I know I had an issue and it is in my genes.”
Mitchell, the University of Maryland epidemiologist, believes nutritional genomics has the potential to one day help decide which diets are best for people. He predicts it could also eventually lead to new treatments for various diseases and medical conditions. But more research needs to be done to validate the potential benefits.
“There is a lot going on in the field,” he said. “We have to be skeptical when see results from early studies. We want to see results repeated before we believe them.”