Is mycoprotein effective for reducing cardiovascular disease risk? Original paper

In this randomized controlled trial in participants with high cholesterol, daily consumption of meals containing mycoprotein (as opposed to meat or fish) decreased LDL cholesterol levels.

The effect of a dietary intervention involving mycoprotein-containing food products on cardiometabolic risk factors in participants with high cholesterol.

The primary outcome was the change in the total cholesterol level. The secondary outcomes were levels of LDL-C, HDL-C, triglycerides, blood glucose (a combined outcome of fasting glucose and postprandial glucose 3 hours after breakfast), and C-peptide.

72 adults (average age of 44; 46 women, 26 men) with overweight or obesity and high cholesterol (more than 193 mg/dL or 5.0 mmol/L).

All of the participants reported following an omnivorous diet.

In this 4-week randomized controlled trial, the participants received protein-equated meals containing either mycoprotein or meat/fish (the control).

The amount of mycoprotein consumed per day was based on the participant’s body weight:

• 150 grams per day for participants with weights under 60 kg
• 180 grams per day for participants with weights of 60–80 kg
• 210 grams per day for participants with weights over 80 kg

No other dietary restrictions or recommendations were provided.

To monitor dietary adherence, the participants met virtually with a member of the research staff weekly, during which 24-hour dietary recalls were conducted.

Compared to the control group, both total cholesterol and LDL-C decreased by 11.6 mg/dL (0.3 mmol/L) in the mycoprotein group.

Additionally, compared to the mycoprotein group, blood glucose and C-peptide levels increased in the control group (+23% and +45%, respectively vs. no change).

Mycoprotein is produced by continuous fermentation of the fungus Fusarium venenatum. It is a rich source of high-quality protein and has been shown to be comparable to milk protein for stimulating muscle protein synthesis.^[1]

The most notable finding in the summarized study is a reduction in total cholesterol and LDL-C of 11.6 mg/dL or 0.3 mmol/L. This is noteworthy because the dietary intervention only involved swapping meat/fish with mycoprotein. By comparison, studies involving the adoption of a vegan diet have reported a reduction in LDL-C of approximately 8.5 mg/dL or 0.22 mmol/L, on average.^[2] However, studies involving the adoption of a Mediterranean diet have not consistently observed a reduction in LDL-C.^[3]

Several other studies have tested whether a mycoprotein-based dietary intervention reduces blood lipid levels. Both participants with normal and high cholesterol levels have been evaluated, and collectively, the results of these studies indicate that daily consumption of mycoprotein for 1–8 weeks can reduce LDL-C levels, especially in participants with high blood cholesterol levels at baseline.^{[4][5][6][7][8][9]}

Less research has been done to determine the effect of mycoprotein consumption on measures of glycemic control. According to the results of a few acute trials — which had participants consume either mycoprotein or soy protein, chicken, or milk protein, and then measured the postprandial metabolic response for up to a few hours — glucose levels were not lower when mycoprotein was consumed, but there was limited evidence to suggest that insulin levels were lower during the early portion of the postprandial phase.^[10]

With respect to longer-term trials, a 7-day randomized controlled trial had physically active, young adults follow identical diets, with the exception of one group consuming meat/fish at lunch and dinner each day and the other group consuming mycoprotein at these meals. No differences were found between groups for measures of glycemic control, including the average 24-hour glucose level.^[5] In a separate 14-day randomized crossover trial, men without apparent health conditions consumed either mycoprotein or a calorie-equated amount of red and processed meat daily. It was found that neither dietary intervention significantly affected fasting glucose.^[4]

The effect of mycoprotein on cardiometabolic risk factors seems to be mostly related to its dietary fiber content. In the summarized study, the most notable difference in dietary intake between groups was in terms of fiber. In the mycoprotein group, daily fiber intake increased from 22 to 33–36 grams per day, about 10 grams of which was provided by mycoprotein. In comparison, daily fiber intake remained steady at 19–20 grams per day throughout the study in the control group.

Previous research indicates that increasing total fiber intake can reduce blood cholesterol levels,^[11][12] but it seems that the type of fiber consumed, rather than the total amount, is the primary determinant of this effect.^[13] Specifically, viscous soluble fiber is the most effective for reducing LDL-C,^[14] and about two-thirds of the fiber within mycoprotein is a type of viscous soluble fiber called beta-glucan.

Another difference in dietary intake between groups that may have contributed to changes in blood lipids is dietary cholesterol. Average dietary cholesterol intake decreased from 248 to 136 mg/day in the mycoprotein group, whereas in the control group, average dietary cholesterol intake remained relatively steady at 229 mg/day.

A 2019 meta-regression analysis of 55 randomized controlled trials reported that every 100 mg per day increase in dietary cholesterol intake was predicted to increase LDL-C by about 4.5 mg/dL.^[15] An increase in dietary cholesterol intake tends to lead to a parallel increase in saturated fat intake, and an increase in saturated fat intake has been consistently demonstrated to increase blood cholesterol levels.^[16][17]

A more recent analysis only included trials that compared a plausible difference in dietary cholesterol intake between groups (i.e., studies with a difference of 1,000 mg/day or more between groups were excluded), and trials that did a pretty good job of ensuring that the groups consumed similar overall diets, meaning the ratio of saturated to polyunsaturated fat was not significantly different between groups. Under these parameters, it was unclear whether increasing dietary cholesterol intake increased LDL-C.^[18]

It should be highlighted that significant interindividual variation has been reported with respect to changes in dietary cholesterol intake and changes in blood cholesterol levels. Due to genetic and biological differences, such as in the absorption of dietary cholesterol and the body’s ability to downregulate endogenous cholesterol synthesis,^[19][20][21] some people experience a substantial rise in blood cholesterol levels when they increase their dietary cholesterol intake.

Variability in the LDL-C response to an increase in dietary cholesterol intake

The lower-cholesterol diet (LC) contained 80 mg of cholesterol per 1,000 calories, while the higher-cholesterol diet (HC) contained 200 mg per 1,000 calories. Adapted from Sehayek et al., 1998, J Lipid Res.

As alluded to above, if incorporating mycoprotein-containing food products in the diet replaces animal-based protein sources rich in saturated fat, then a significant decrease in blood cholesterol levels will likely occur as a result of the replacement. However, in the summarized study, saturated fat intake did not significantly differ between groups, so this potential factor did not contribute to the results.

All in all, incorporating mycoprotein-containing food products in the diet is an efficacious approach to lower LDL cholesterol levels, particularly if it replaces meat. However, swapping meat for mycoprotein doesn’t seem to have much of an effect on measures of glycemic control.

The change in body weight did not differ between groups. Both groups lost 0.8–1.0 kg.

A few of the researchers were employees of Marlow Foods, the company that sponsored the study and manufactures the evaluated mycoprotein-containing food products.

A potential limitation of this study is that, because the study was conducted during the COVID-19 pandemic, the participants collected their own blood samples and mailed them to the researchers. Relatedly, although the participants were instructed to maintain their usual physical activity habits, physical activity was not monitored. It’s possible that the deterioration in glycemic control observed in the control group was a consequence of a change in physical activity related to COVID-19 lockdown restrictions.