The paper, titled Seven Guidelines for a Health Microbiota, was penned by nutritionist Meghan Jardine, RD for the Physicians Committee for Responsible Medicine (PCRM). Jardine noted in the paper that the questions surrounding the health of the human gut are complicated by the fact that while humans are all genetically very similar to one another, our microbiomes are not.
“While we share 99.9% of our genes with other people, we only share 10% of our microbiome, the collective genetic makeup of our bacterial populations.We’ll continue to learn more about how the microbiome influences human health as the rise of metagenomics, the study of bacteria living inside our personal ecosystem, unfolds,” Jardine wrote.
Plant foods first
Jardine offers the following guidelines for physicians to help patients build a set of habits that can support overall gut health:
- Build meals around plant-based foods: vegetables, fruits, whole grains, and legumes.
- Aim to consume at least 50 to 55 grams of fiber daily.
- Include at least 5 to 8 grams of plant-based prebiotics per day. Aim for at least two servings of prebiotic foods outlined in the guidelines below.
- Add fermented foods, or probiotics, to your diet.
- Avoid red meat, high-fat dairy products, fried foods, food additives, and advanced glycation end (AGE) products.
- Limit fat intake, especially if you have or are at risk for type 2 diabetes.
- Use antibiotics only when necessary and avoid using for viral illnesses.
Like most dietitians, Jardine’s recommendations follow a food-first model, and come down heavily on emphasizing plant-based foods. She cites research on fiber that shows that in as little as two weeks a typically high-fat, low-fiber Western diet heavy on processed meats can undo the protective aspects of a diet rich in high-fiber plant foods and vice versa. Jardine recommends a diet rich in plant foods and one which contains at least 50 to 55 grams of fiber a day, which is far above the IOM recommendations of 38 grams a day for a man and 30 grams for a woman.
Jardine does use the terms ‘prebiotic’ and ‘probiotic’ in her paper. But she advocates for ingesting these ingredients in the form of foods. For prebiotic activity, she recommends raw leafy greens as well as other food sources, and for probiotics, she advocates eating sauerkraut, kimchi or other fermented foods.
Too much choice?
Jardine said she is not against supplementation per se. But she said that when crafting recommendations for physicians, it’s hard to put together a simple message when there are so many ingredients on the market and there are so many studies of varying quality behind them. And the patients are variegated, too.
“I’m a little skeptical of probiotics. I know there is research that supports [these ingredients] but it’s hard to make a blanket recommendation because people are so different,” she told NutraIngredients-USA.
“I’m a dietitian, so I always go to food first. The paper was not meant to imply that people shouldn’t take probiotics, but how would I make a recommendation about probiotics without going into all the different strains and the different indications? Many of the studies are short term and of small size. I think we need to give the research some time to catch up with the incredible growth in the industry and the growth in consumer interest,” she said.
More education needed
George Paraskevakos, executive director of the International Probiotics Association, said Jardine’s recommendations are typical of what he sees in the industry. The research behind probiotics continues to make an increasingly compelling story for efficacy, but the field is advancing so quickly that many experts are unaware of the most recent developments. So first and foremost, there is a need for more education, he said.
“If you look at the website of the PCRM, it’s all about healthful diets and their effect on prevention. There is no mention of any supplementation of other types on their website, either. They are more focused on the food chain,” he said.
“The research has advanced in a significant way in just the past few years and not only in gut health but in indications beyond that such as immune support. The research behind probiotics is not lacking, far from it. I think this is more a question of getting the message out, communicating the benefits of these ingredients. This is where the IPA comes in and we’re going to work hard in this coming year to increase awareness,” Paraskevakos said.