University of Bath research unveils the hidden risks of ketogenic diets, highlighting increased cholesterol and decreased beneficial gut bacteria

In a groundbreaking study from the University of Bath, researchers have uncovered concerning effects of the ketogenic diet on cholesterol levels and gut health. Published in Cell Reports Medicine, this research involved 53 healthy adults who followed either a moderate-sugar diet, a low-sugar diet, or a ketogenic low-carbohydrate diet for up to 12 weeks.

Participants on the ketogenic diet experienced significant increases in cholesterol levels, particularly in small and medium-sized LDL particles. This increase was accompanied by a rise in apolipoprotein B (apoB), a protein linked to plaque buildup in arteries. In contrast, those on the low-sugar diet saw a notable reduction in LDL cholesterol.

The keto diet also adversely affected gut microbiome composition, notably decreasing levels of Bifidobacteria. This beneficial bacteria, often found in probiotics, plays a crucial role in producing B vitamins, inhibiting harmful pathogens, and reducing cholesterol. Participants on the low-sugar diet did not experience similar changes in their gut microbiota.

In terms of glucose tolerance, the ketogenic diet led to a reduction in the body’s ability to handle carbohydrates effectively. Despite this, both the keto and low-sugar diets resulted in fat loss, with the keto diet producing an average loss of 2.9 kg of fat mass per person, compared to 2.1 kg for the low-sugar diet.

The study also noted significant shifts in lipid metabolism and muscle energy use with the keto diet, indicating a shift from glucose to fats as the primary fuel source. Interestingly, both diets achieved fat loss without altering physical activity levels, which contrasts with previous findings where dietary interventions affected physical activity.

Dr. Aaron Hengist, the lead researcher, expressed concern over the long-term health implications of the keto diet. “Despite the fat loss benefits, the increase in unfavourable fats in the blood could lead to serious health issues, including heart disease and stroke, if sustained over time.”

Dr. Russell Davies, who led the microbiome research, highlighted the impact on gut health. “The reduction in fibre intake with the keto diet, which dropped to about 15 grams per day—half the NHS recommended amount—could have significant long-term health consequences, including digestive disorders and weakened immune function.”

Professor Javier Gonzalez, overseeing the research, pointed out the glucose tolerance issue. “The keto diet reduces fasting glucose levels but also impairs the body’s ability to handle carbohydrates. This could pose a risk for developing type 2 diabetes if individuals switch back to a higher carbohydrate diet.”

The study’s findings suggest that while the ketogenic diet can be effective for fat loss, it comes with metabolic and microbiome effects that may not be suitable for everyone. In contrast, a low-sugar diet aligns with government recommendations and supports fat loss without apparent negative health impacts.

Analysis

• Political: This study might influence dietary guidelines and policies. As governments and health organizations continuously update nutritional recommendations, the findings could impact how ketogenic diets are perceived and regulated. Policymakers might use this data to reinforce recommendations against high-fat diets in favor of low-sugar alternatives.
• Social: The ketogenic diet has gained popularity as a weight-loss strategy, reflecting broader societal trends towards high-fat, low-carb diets. This study could challenge the diet’s positive image and spark debates on the need for more balanced dietary approaches. It also underscores the importance of evidence-based recommendations in public health nutrition.
• Racial: The study does not specifically address racial differences in response to ketogenic diets. However, dietary responses can vary among different racial and ethnic groups due to genetic, metabolic, and lifestyle factors. Future research could explore these aspects to provide more personalized dietary guidelines.
• Gender: The research does not differentiate between gender responses to the ketogenic diet. Gender-based differences in metabolism and nutritional needs could affect how individuals experience the diet’s impact. Understanding these differences could lead to more tailored dietary advice for different genders.
• Economic: The findings may influence economic aspects related to dietary supplements and food industries. The rising popularity of ketogenic diets has led to a market for keto-friendly products. If these diets are proven to have adverse effects, there could be economic repercussions for companies promoting them, as well as shifts in consumer preferences towards low-sugar products