In human nutrition, individualizing dietary recommendations based on genetic information is currently a popular trend, according to an announcement from the Technical University of Munich (TUM) in Germany.

A team at TUM has systematically analyzed scientific articles and reached the conclusion that there is no clear evidence that genetic factors have an effect on the consumption of total calories, carbohydrates and fat, TUM said. According to the current state of knowledge, the expedience of gene-based dietary recommendations has yet to be proved, TUM added.

Does this study have implications for animal nutrition, where nutrient recommendations increasingly are becoming tailored to animal genotype?

TUM pointed out that obesity and being overweight have become a global health problem in people. According to the World Health Organization, 39% of adults in European Union countries are overweight. In Germany, more than 50% of adults are overweight, and almost one-fifth currently are considered obese, according to the Robert Koch Institute, TUM said. This is primarily due to a modern lifestyle characterized by low physical activity and high-calorie foods.

Genetic factors also play a role in the occurrence of obesity. To date, around 100 genes (loci) have been identified that are related to the body mass index (BMI), TUM reported. However, the functioning of these genes and the biological mechanisms behind them are still largely unknown.

Investigating the relationship between genetic factors and nutrition can shed light on whether genes linked to BMI play a role in nutrition, TUM said.

The TUM team's initial database search revealed more than 10,000 scientific articles that were concerned with the topic. Of these, 39 articles were identified for a relationship between genetic factors and total energy, carbohydrate or fat consumption, TUM noted.

"In all studies, we most frequently encountered the fat mass and obesity (FTO) associated gene, as well as the melanocortin 4 receptor gene (MC4R). There are indications of a relationship between these two genes and total energy intake," explained Dr. Christina Holzapfel from the Institute of Nutritional Medicine at TUM.

However, the evaluation of the studies did not provide a uniform picture. "There is only limited evidence for the relationship between the FTO gene and low energy intake as well as between the MC4R gene and increased energy intake," Holzapfel said.

Hence, to date, no indications exist that certain genetic factors are associated with the total intake of calories, carbohydrates and fat, TUM said.

The current state of knowledge is still too limited to derive individual nutritional recommendations based on genetic information, such as for weight management, Holzapfel explained. Expert associations also agree with that statement.

"Human studies with detailed phenotyping, e.g., based on a genetic pre-analysis of the participants, are necessary in order to determine the interactions between genetic factors and diet on bodyweight," she said. "The 'Personalized Nutrition & eHealth' Junior Research Group funded by (Germany's) Federal Ministry of Education & Research, which is part of the enable nutrition cluster, is working precisely on this."

Preliminary CBD clinical trials

Dr. Stephanie McGrath, a neurologist at Colorado State University’s James L. Voss Veterinary Teaching Hospital, has revealed initial findings from a groundbreaking study to assess the use of cannabidiol (CBD) for dogs with epilepsy, according to an announcement.

Based on her research, she found that 89% of dogs that received CBD in a clinical trial saw a reduction in the frequency of seizures.

“Overall, what we found seems very promising,” she said.

According to Colorado State, 16 dogs were enrolled in the clinical trial. Nine dogs were treated with CBD, which has 0.3% or less of the psychoactive component of cannabis (THC); seven dogs in a control group were treated with a placebo. CBD is not considered marijuana and can be used for research purposes based on the 2014 farm bill, the university explained.

McGrath initially decided to pursue this line of research after receiving frequent calls from clients and other veterinarians with questions about CBD.

“People are using CBD, and they are excited about its potential,” she explained. “It’s a topic that is gaining traction in the media, but we truly know very little about it from a scientific standpoint.”

Colorado State said McGrath is pursuing the following questions: Is CBD effective? What is the amount or dose to recommend for canine patients? How is it absorbed in the body? What effect does it have on things like metabolism?

McGrath’s research team previously conducted a pharmacokinetic study (looking at how a drug or medication is absorbed in the body and metabolized) and a safety study in 30 healthy dogs. This helped determine the approximate amount of CBD to use for the clinical trials at Colorado State.

Dogs enrolled in the study were randomly assigned to a treatment or placebo group. The study was double-blind, which means the veterinarians and medical staff did not know which dogs were being treated with CBD until the research was concluded.

McGrath presented the research findings July 16 at the annual convention of the American Veterinary Medical Assn. She will share additional results from this trial, as well as a study of CBD for dogs with osteoarthritis, later this year.

“This pilot study is important, and it does seem like there is a positive effect from the use of CBD for dogs with epilepsy,” McGrath said.

Colorado State launched a larger clinical trial with CBD for dogs with epilepsy in January 2018. McGrath said the aim of that study, funded by the American Kennel Club Canine Health Foundation, is to enroll 60 dogs.