+AA
Fr
Back
Evidence Summary

What is an Evidence Summary?

Key messages from scientific research that's ready to be acted on

Got It, Hide this
  • Rating:

The Portfolio diet in combination with an NCEP Step II diet may reduce multiple cardiometabolic risk factors

Chiavaroli L, Nishi SK, Khan TA, et al. Portfolio dietary pattern and cardiovascular disease: A systematic review and meta-analysis of controlled trials Prog Cardiovasc Dis. 2018;61:43-53.

Review question

What is the effect of the Portfolio diet  in combination with the National Cholesterol Education Program (NCEP) Step II diet on LDL-cholesterol (bad cholesterol) and other risk factors for diabetes and cardiovascular disease (aka cardiometabolic risk factors), compared to the NCEP Step II diet alone?  

Background

The Portfolio diet is a plant-based diet consisting of four types of foods, which research has shown have a cholesterol-lowering effect: ≥ 45 g/day nuts (e.g., peanuts), ≥20 g/day viscous fibre that dissolves in water (e.g., comes from oats, barely, etc.), 2 g/day plant sterols (e.g., plant sterol-enriched margarine), and ≥ 50 g/day plant proteins (e.g., from soy or dried seeds such as beans, lentils or peas). This diet has been recommended in some guidelines developed by world leaders in the fields of diabetes and heart health. The NCEP Step II diet consists of 30% or less calories as total fat, less than 7% calories as saturated fat, and less than 200 mg/day of cholesterol, and is sometimes used with the Portfolio diet. The European Association for the Study of Diabetes, which has not made specific recommendations for the Portfolio diet, ordered a systematic review and meta-analysis to decide if changes to their recommendations were needed. The review focused on the Portfolio diet in combination with the NCEP Step II diet.

How the review was done

This is a systematic review and meta-analysis of five randomized controlled trials and non-randomized controlled trials published between 2002 and 2011, including a total of 439 participants.

  • Participants were adults who were generally between 54-65 years of age and overweight, and who had high cholesterol, but no history of diabetes or cardiovascular disease.  
  • Participants were on an NCEP Step II diet before the start of each study included in the review. Then, during each study, participants received one of two Portfolio diet-related approaches: 1) they were given food so they could follow either the standard Portfolio diet or an enhanced version that was high in monounsaturated fat (e.g., a type of fat found in sunflower oil or avocado); or 2) they were given either routine nutritional advice (two 40-60 minute clinic visits) or intensive nutritional advice (seven 40-60 minute clinic visits) from a dietician about incorporating foods from the Portfolio diet into their own diet.
  • Researchers measured changes in: indicators for blood sugar control; LDL-cholesterol and other types of fat found in the blood (total cholesterol [TC], triglycerides [TG], non-HDL cholesterol, and HDL-cholesterol); apolipoprotein B [apoB] (helps transport fat); blood pressure; C-reactive protein [CRP] (a marker for inflammation); estimated 10-year risk of coronary heart disease; and body weight. 
  • Results were compared to people in control groups who either received dietary advice on the NCEP Step II diet or food that met the criteria of the NCEP Step II diet so they could follow it.
  • All trials included in the review received funding from both agency (e.g., government funded health research agencies) and industry (e.g., leaders in the field of diabetes) organizations.

What the researchers found

No trials that examined the effect of the Portfolio diet on measures of blood sugar control were found. Overall, the Portfolio diet in combination with an NCEP Step II diet was effective in reducing the following cardiometabolic risk factors in adults with high cholesterol, compared to the NCEP Step II diet alone:

  • LDL-cholesterol, TC, TG, non-HDL- cholesterol, and apoB
  • Systolic and diastolic blood pressure
  • The inflammation marker CRP
  • Estimated 10-year risk of coronary heart disease

However, there was no effect on HDL-cholesterol (aka good cholesterol), and weight. The evidence that supported the findings for LDL-cholesterol, TC, TG, non-HDL-C, apoB and weight was rated as being of high certainty, while the evidence for HDL-cholesterol, blood pressure, CRP, and 10-year coronary heart disease risk was rated as being of moderate certainty. More research with larger, higher quality studies is needed to confirm the findings in this review, and to establish the diet’s impact on actual heart-related events.   

Conclusion

The Portfolio diet in combination with the NCEP Step II diet may lower multiple cardiometabolic risk factors including LDL-cholesterol, the main target for cardiovascular disease prevention. These reductions may improve the estimated 10-year coronary heart disease risk.

 




Glossary

Control group
A group that receives either no treatment or a standard treatment.
Coronary heart disease
Also known as coronary artery disease (CAD), is a narrowing of the blood vessels (coronary arteries) that supply oxygen and blood to the heart.
Diastolic
The lower number in a blood pressure reading. It is the pressure when the heart rests between beats.
Meta-analysis
Advanced statistical methods contrasting and combining results from different studies.
Non-randomized controlled trial
Studies where people are assigned to one of the treatments but not purely by chance.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Risk factors
Aspects making a condition more likely.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.
Systolic
The higher number in a blood pressure reading. It is the pressure in the arteries when the heart beats.
Vascular
The body's network of blood vessels. It includes the arteries, veins, and capillaries that carry blood to and from the heart.

Related Web Resources

  • Preventing deep vein thrombosis

    Evidently Cochrane
    Compression stockings help to prevent deep vein thrombosis (blood clots and swelling) after surgery. You can choose to wear thigh or knee length stockings.
  • Coronary artery disease risk screening

    Health Link B.C.
    Men over 40 and women past menopause or over 50 should get screened for coronary artery disease (CAD) every 1 to 3 years. Your risk is higher if you have diabetes, high blood pressure, abdominal obesity, kidney disease, family history of CAD or if you smoke.
  • High cholesterol: Does reducing the amount of fat in your diet help?

    Informed Health Online
    Eat less saturated fats in your diet to help prevent heart disease. Eat less meat, butter, cheese and cream to improve your health long-term.
DISCLAIMER These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (info@mcmasteroptimalaging.org).

Register for free access to all Professional content

Register
Want the latest in aging research? Sign up for our email alerts.
Subscribe
© 2012 - 2019 McMaster University | 1280 Main Street West | Hamilton, Ontario L8S4L8 | +1 905-525-9140 | Terms Of Use