Scientists discover an unexpected connection between gut and heart health

One of the buzziest (and most controversial) health trends is the ketogenic diet.

Embraced by many, keto revolves around a high-fat, low-carb, and adequate-protein way of eating. However, many scientists are skeptical of the diet, arguing its downsides may outweigh its benefits.

A study published Friday in the journal Science reinforces the main argument against keto: a high-fat diet can lead to long-term health problems.

The study team examined the link between a high-fat diet and heart disease, finding gut bacteria can influence this relationship. We can control these intervening factors by moderating the amount of fat in our diet.

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Why it’s a hack — When you eat a high-fat diet, a few things happen:

First, the diet increases intestinal inflammation, damaging intestinal cells. At the same time, the diet can impair intestinal cell mitochondria (the powerhouse of the cell), causing those cells to churn out more oxygen and nitrate.

Oxygen and nitrate stimulate two things: the proliferation of harmful bacteria like E. coli, and the production of the metabolite TMA (trimethylamine). The liver then converts TMA into TMAO (trimethylamine-N-oxide). TMAO can increase the relative risk of mortality, especially when it comes to heart disease.

The inflamed, weakened intestines allow for the possibility of TMAO to travel to the heart, where it settles in the arteries as plaque that restricts blood flow.

Critically, you can avoid this process — the inflammation, the harmful bacteria, the surplus TMAO — by eating a balanced diet.

The lauded keto diet, for example, has been shown to pose the risk of heart disease. Red meat can be a big part of keto and red meat is high in choline — a nutrient that gets converted into TMA (and then into TMAO).

Science in action — The study team examined three distinct but interconnected factors in the mice:

• Changes to the intestinal lining
• Mitochondrial dysfunction
• Effects of high-fat diets on E. coli growth

The researchers started by raising mice on a high-fat diet. Then, they introduced E. coli into the mice’s systems in an effort to make their guts resemble the human gut.

Subsequently, the high-fat diet led to intestinal inflammation and damaged intestinal cells. The E. coli in the mice flourished because of all the extra oxygen and nitrate.

These three factors — intestinal inflammation, dysfunctional mitochondria, and harmful bacteria — all conspire to increase the risk of heart disease.

How this affects longevity — You’ve probably heard high-fat diets aren’t the best, but this study provides a new reason why.

It’s established that a high-fat diet can result in obesity, which in turn can prompt a slew of health conditions, ranging from diabetes to an increased risk of heart attack. This study informs our understanding of how fat affects our individual cells and how they function.

Previously, this study team found the relationship between cells lining the intestines and gut microbes allows for a healthy microbiome. Now, it’s understood that a diet high in fat can disrupt this relationship by promoting the growth of “bad” microbes.

A study of the mice included in this research revealed a drug called 5-aminosalicylic acid, typically used to treat bowel disease, could prevent the negative reaction prompted by diet.

While the study team hopes they can use this information to develop a similarly successful therapeutic for humans, for now, the best solution comes down to what we choose to eat.

Hack score out of 10 — 🍖🍖🍖🍖🍖🍖 (6/10)