Eat your hemp heart out — the benefits of hemp seeds on gut health

One hundred years ago, fish and shellfish were frequent visitors to dinner plates around the world. While not common knowledge at the time, the fish had oils containing about equal parts omega-3 and omega-6 polyunsaturated fatty acids, essential components for cell membranes, that are primarily absorbed through the diet. 

While modern civilizations still love a fresh filet or sushi roll, oils from seed and vegetable sources like sunflowers, canola and corn have become increasingly dominant in the global food supply. These oils are easy to cook with and boast many different health benefits of their own, but they also contain significantly more omega-6 fatty acids than omega-3. 

Weicang Wang, an assistant professor in Purdue’s Department of Food Science, says this is a classic case of too much of a good thing. The balance of omega-3 to 6 fatty acids is more important than just getting the nutrients.

“The omega-6 to omega-3 ratio in human diets has changed substantially over the last century, primarily due to industrialization, changes in food processing and the increased use of vegetable oils rich in linoleic acid (omega-6),” Wang said. “Current Western diets often have ratios ranging from 10:1 to 20:1, with excess omega-6 fatty acids. Many emerging studies have shown that too high a ratio in omega-6 fatty acids in our diet is related with increased risk of many inflammatory diseases.”

Fortunately, the potential solution lies in making small changes to the diet. Some seed oils, like those made from flaxseeds, have a more balanced ratio, and other emergent foods could help supplement omega-3 fatty acids.

In collaboration with Senay Simsek, department head and Dean's Chair in Food Science, Wang’s team is currently exploring the health benefits of dietary hemp seeds, which are derived from industrial hemp—a variety of Cannabis sativa that contains no or only trace amounts of tetrahydrocannabinol, or THC.

Hemp seeds are one part of the plant becoming familiar with supermarket shelves. Not only does hempseed oil have a 2.5:1 ratio of omega-6 to omega-3 fatty acids, but the seeds also contain an abundance of protein, fiber, antioxidants and all essential amino acids. The seeds are often sold as hemp hearts, which have had the tough exterior of the seed removed so they are easier to cook or consume. 

In their recently published paper, Simsek and Wang’s team systemically reviewed the latest evidence in hemp seed and gut health, and they are currently conducting research to further investigate the impact of dietary hemp seeds on gut health. 

Wang said, “It’s an exciting topic to discuss how to improve our gut microbiome to improve our overall health, and the gut itself is, indeed, linked with all other major organs. Some studies have shown that a healthy gut will improve our mental health. And, on the other hand, if our gut has some disease or inflammation, it could influence our brain health and liver health.”

Impacting over three million Americans is a group of conditions called Inflammatory Bowel Disease (IBD), also known as colitis. IBD includes Crohn's disease and ulcerative colitis. Associated with stomach pains, cramping, fatigue and changes in appetite and weight, IBD is incurable. However, one of the promising treatments is to manage the symptoms by changing what someone eats.

In his preliminary study, Wang found that a diet that contained hempseed powder for a month had less tissue damage in the gut when later contracting IBD than when on a normal diet. The hempseed group also had greater amounts of tight junction proteins that tie gut cells together and prevent leakage of harmful bacterial products, such as endotoxins.

“We also do see some change in molecular levels. For example, we looked at some other disease markers, like pro-inflammatory cytokine level. Basically, these cytokines are the protein secreted by immune cells, so they make inflammation happen. In IBD, many immune cells will be over activated, so they produce much more cytokine than they are supposed to,” Wang said.

IBD leads to nearly double the level of inflammatory cytokines. The hempseed-enhanced diet group under IBD stress showed levels of cytokines similar to a group without IBD.

In collaboration with Tingting Ju in Purdue’s Department of Animal Sciences, Wang also found that eating hemp seed also increased amounts of Bifidobacterium in the gut—commonly marketed as a beneficial probiotic due to its role in supporting gut and immune health. The gut microbiome also boasted a decline in the population of Staphylococcus, a harmful bacterium which is commonly associated with IBD.

Wang plans to repeat his experiments and look at other organs that may be impacted by a hempseed diet and the subsequent changes in gut health. He would also like to test hemp seeds’ effect on the gut when IBD is already present.

Wang and the Purdue Hemp Team hope this research helps establish hemp seeds and hearts as regular parts of the average person’s diet to improve overall human health and to relieve pain experienced by those with chronic gastrointestinal diseases.