Study shows hidden cardiovascular risks in real-carb low-carb diets

Study shows hidden cardiovascular risks in real-carb low-carb diets

A new study shows that while low-fat diets, saturated fats and carbohydrates are guilty of guilt, high cholesterol and salt intake can still threaten heart health.

In a recently published study in theInternational Journal of Cardiology, Cardiovascular Risk and PreventionResearchers examined dietary differences in a real-world high-carbohydrate, high-fat carbohydrate population and their relationship to cardiovascular risk factors.

LCHF diets are popular for blood sugar control and weight loss. However, personal beliefs and reasons can influence dietary decisions. The main feature of LCHF diets is the decrease in dietary carbohydrates, which are mainly replaced by fats. Nutritional recommendations tailored to patients preferring LCHF diets are not available. LCHF diets typically include natural, unprocessed foods.

Saturated, high-fat foods are preferred over low-fat alternatives. However, saturated fats and cholesterol are associated with higher risk of cardiovascular disease, while unsaturated fats provide benefits. Several studies showed significant increases in low-density lipoprotein (LDL) cholesterol levels in healthy individuals following a low-carbohydrate, high-fat (LCHF) diet.

About the study

Activity level didn't move the needle: Despite participants' mean physical activity level (PAL) of 1.6 - daily exercise like walking - showed no measurable impact on blood lipids or blood pressure.

The present study examined dietary variation in a real-world low-carbohydrate (LCHF) population and its associations with cardiovascular risk factors. The team recruited volunteers who followed an LCHF diet for at least three months. The subjects did not use lipid-lowering medications and were free of familial hyperlipidemia. Participants' weight, height, hip and waist circumference, and blood pressure (BP) were measured. Urine and blood samples were also collected.

Participants' activity was monitored for a week to estimate total energy expenditure (TEE). Diet recall interviews were conducted to assess the nutritional composition of the diet. Energy intake (EI) was compared to tea. Subjects with plausible EI values ​​were considered acceptable reporters. The subjects also reported whether they were weight stable. Furthermore, the basal metabolic rate, physical activity (PAL) and food intake (FIL) were calculated.

The Shapiro-Wilk test assessed normal distributions and stepwise linear regression modeling was performed. Outcome variables included glycated hemoglobin (Hba1c), systolic blood pressure (SBP), lipid profile, and diastolic blood pressure (DBP). Explanatory variables were age, gender, PAL, Fil, EI, body mass index (BMI), sodium intake, cholesterol intake, alcohol consumption, saturated fatty acids (SFAs), and energy fraction (E%) from protein, fat, and carbohydrates.

The step model was bidirectional and started as an intercept-only model, and predictive variables were added sequentially. The next best predictive variable was identified based on the Akaike information criterion. The primary statistical analyzes included only acceptable reporters. All participants, including their reporting stability, were included in sensitivity analyses.

Results

Saturated fat remained neutral—but with an asterisk: While the study did not find a direct link between saturated fats and cardiovascular risks, it cautiously notes that this reflects unique metabolic adaptations in long-term LCHF dieters, not a universal rule.

A total of 100 volunteers took part in this study. Nearly two-thirds were female, non-smokers and 83 were acceptable reporters. The average age and BMI of the participants were 48.7 years and 25.7 kg/m², respectively. The median SBP, Hba1c, total cholesterol (TC), LDL cholesterol, and high density cholesterol (HDL) were 120 mmHg, 35 mmol/mol, 6.2 mmol/L, 3.8 mmol/L, respectively. 1.8 mmol/l.

The median carbohydrate intake was low (8.7 e%) and compensated with a higher EI from fats (72.3 e%). Likewise, dietary fiber intake was low at 13 g/day. Advanced age was associated with increased LDL, TC, BP, Hba1c and HDL. Furthermore, male gender was associated with higher HbA1c, triglycerides and lower HDL, while increased BMI was associated with reduced TC and HDL and increased DBP and triglycerides (conflicting trends in the general population).

Additionally, dietary cholesterol levels were associated with higher TC, HDL, and LDL. Protein intake was associated with lower HDL and DBP(Aligned with known antihypertensive effects, but typical protein-HDL associations)while fiber intake was associated with slightly higher HbA1c(Although the paper notes that this could be a chance to find)and lower TC and LDL. Alcohol consumption was associated with higher triglycerides and lower HbA1c. There were no associations of SFA or carbohydrate intake with any outcome variable.

EI and energy expenditure were not associated with meaningful changes in any outcome. In analyzes involving all subjects, there was an association between male gender and higher SBP and between protein intake and lower SBP. These associations were not observed when individuals reporting weight stability were included.

Conclusions

In summary, carbohydrate intake in this real-world LCHF population was low, and minor variations were not associated with cardiovascular risk factors. Cholesterol intake was high and associated with poor lipid profiles, while sodium intake was associated with higher blood pressure. These findings have also justified the concerns of low fiber intake in LCHF diets.

Low fiber intake was associated with a poor lipid profile. Because the study was cross-sectional, the results may be inconclusive and longitudinal studies are needed to further examine the associations. Overall, these results reinforce dietary recommendations for fiber-rich foods in LCHF diets while avoiding excessive cholesterol and salt intake.

I think it is a questionable study in which the authors have ties to the pharmaceutical industry. Here is the “Statement of Competing Interest” that was not included in this article:

The authors declare the following financial interests/personal relationships that may be considered potential competing interests: Mattias Brustrom reports a relationship with Amarin Pharma Inc. that includes: consulting or advisory services and speaking and lecture fees. Mattias Brunstrom reports a relationship with AstraZeneca AB that includes: Consulting or consulting. Mattias Brunstrom reports a relationship with Medtronic Inc that includes: speaking and lecture fees. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this article.

Sources: