Portfolio diet delays heart risk and lowers cholesterol in young adults

Portfolio diet delays heart risk and lowers cholesterol in young adults

New research shows that even modest adherence to the Portfolio Diet, a plant-based cholesterol-lowering strategy, can significantly reduce cardiovascular risk factors in young adults and delay the onset of heart disease by more than a decade.

Researchers at the University of Toronto conducted a cross-sectional study of multi-ethnic cohorts to evaluate the effect of the portfolio diet on a range of cardiovascular risk factors, including low-density lipoprotein cholesterol (LDL-C). The results will be published in the journalBMC public health.

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Specific food effects: The study found that nuts and plant proteins were superstars, and higher intakes were linked to better cholesterol levels and lower blood pressure.

Cardiovascular diseases are a major cause of mortality worldwide. Several health conditions increase the risk of cardiovascular disease, including diabetes, obesity, hypertension and hyperlipidemia.

Exposure to hyperlipidemia (high cholesterol) has been found to increase the risk of cardiovascular disease in a dose-dependent manner. Among various lipid molecules, LDL-C has been found to have a causal association with a higher incidence of cardiovascular disease. Early management of hyperlipidemia from a younger age is therefore an effective preventative strategy against cardiovascular disease.

The Portfolio Diet is a plant-based therapeutic nutritional strategy specifically designed to reduce blood cholesterol levels. It contains five types of cholesterol-lowering food components, including plant protein, viscous fiber, nuts, phytosterols and monounsaturated fatty acids. Importantly, the Portfolio Diet Score also assigns reverse points for saturated fat and cholesterol intake from animal sources, so lower intake of these foods is considered better adherence.

Existing clinical evidence shows that a portfolio diet is effective in reducing multiple cardiovascular risk factors, including LDL-C, total cholesterol, triglycerides, C-reactive protein, and systolic and diastolic blood pressure in middle-aged adults.

Given the cardioprotective effects of portfolio nutrition and the lack of information about its effectiveness in ethnoculturally diverse populations, the current study aimed to evaluate the associations of the diet with LDL-C and other established cardiovascular risk factors in an ethnoculturally diverse population of young adults.

Study design

The study analyzed data from 1,507 men and women in the Toronto Nutriigenomics and Health study, a cross-sectional study examining the effects of dietary intake and genetic variation in chronic disease biomarkers in young Canadians from diverse ethnocultural backgrounds.

Participants' dietary intake was assessed using a validated food frequency questionnaire, and their adherence to the Portfolio Diet was assessed using the Portfolio Diet Score. Appropriate statistical analyzes were performed to determine associations of the score with LDL-C and other established cardiovascular risk factors.

It is important to note that the design as a cross-sectional observational study does not allow causality to be determined.

Study results

The role of saturated fat: Even small increases in saturated fat intake counteracted the diet's LDL and blood pressure benefits.

The study included participants from different ethnicities. Those with higher adherence to the Portfolio diet were more likely to be Caucasian, with relatively fewer East Asian, South Asian and other ethnicities in the highest adherence group.

Participants who adhered more strictly to the portfolio diet showed significantly lower levels of LDL-C, total cholesterol, lipoprotein cholesterol (non-HDL-C), and systolic and diastolic blood pressure.

Similarly, these participants showed lower body mass index (BMI), waist circumference, body weight and fat mass index (FMI).

The study compared different levels of dietary adherence and found that compared to low adherence, 50% and 100% dietary adherence can delay the onset of increasing cardiovascular risk by 6 and 13 years, respectively.

However, the study found no significant associations between adherence to the portfolio diet and total HDL cholesterol (HDL-C), C-reactive protein (CRP), or fasting glucose levels.

Among the covariates analyzed in the study, gender and ethnicity showed a strong influence on the association of the portfolio diet with total cholesterol and fasting glucose, respectively. According to the results, the influence of diet on total cholesterol levels was stronger in men than in women. Similarly, the impact of diet on fasting blood glucose was greater in East Asians and South Asians compared to other ethnicities.

Investigate significance

Triglycerides Nuance: While overall adherence did not always lower triglycerides, those in the top third saw significant drops.

The study shows the health benefits of a portfolio diet in reducing levels of several cardiovascular risk factors, including LDL-C, non-HDL-C, total cholesterol, systolic blood pressure and diastolic blood pressure. The study also finds that the diet is effective in improving anthropometric measurements, including BMI, waist circumference, body weight and FMI.

While the observed reductions in LDL-C were 0.1 mmol/L or 4% lower among those in the highest compared to the lowest adherence groups, this is comparable to the minimal lipid reduction for each doubling of the dose of a statin drug (a clinically approved lipid-lowering drug). This observation suggests that with greater differences in dietary adherence, a meaningful association with LDL-C may also be observed in young adults.

Life transitions, including leaving home and becoming young adults, are known to negatively impact diet quality. Healthy nutritional interventions are therefore particularly important in this age group to reduce the lifespan of cardiovascular risk factors.

The study recruited young adults from a large urban university campus, which may limit the generalizability of the results. The study analyzed self-reported dietary data, which may introduce some measurement error.

In general, study participants demonstrated lower consumption of portfolio diet components, which may have led to an underestimation of the strength of the observed associations.

In modeled projections, the study considered constant LDL-C levels over time because a single measure of LDL-C is available. Future longitudinal studies using multiple LDL-C measurements are needed for more reliable projections.

Because this was a cross-sectional study, the results reflect associations rather than causal relationships. Prospective longitudinal studies are needed to confirm these results and understand the long-term effects of early introduction of the portfolio diet on cardiovascular health.

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