The portfolio diet isn’t designed to drop pounds. Instead, it aims to lower cholesterol.
Even the phrase "diet plan" may be too much for David J.A. Jenkins, MD, PhD, a University of Toronto professor of nutritional sciences. He’d rather call it a dietary portfolio.
"We are not trying to go for the Atkins diet-type [of] impact," he says. "We'd rather have a concept that can evolve as we learn more and be able to give people the necessary information so that they can create the diet on their own."
The concept is to diversify your nutritional strategies to curb your cholesterol level. Just as you wouldn't bet all your money on a single stock, Jenkins says you shouldn't rely on one kind of healthy food. In other words, don’t put all of your eggs in one basket.
"We are trying to get a paradigm shift [away] from looking at the benefit of a single food," he says. "We want people to look at the combinations of foods – in real diets for real people in the real world – that will carry a range of benefits and reduce a range of risks."
4 Key Foods in the Portfolio Diet
The portfolio diet recipe for lower cholesterol focuses on four kinds of food:
- Soy-based foods. "We are looking at soy-based meat substitutes such as soy burgers, tofu, tempeh, and soy cold cuts," Jenkins says. "And we also used soy milk as a dairy substitute." For Thanksgiving, he suggests, one might replace turkey with "Tofurky."
- As much viscous (sticky) fiber as possible. Viscous fiber is a type of soluble fiber. It forms a gel in your gut and binds to cholesterol so your body doesn’t absorb it. Food sources of viscous fiber include oats, barley, eggplant, okra, berries, and citrus fruit. You can also get viscous fiber with daily servings of psyllium.
- Plant sterol-enriched foods. These include some margarines, or you can get them from dietary supplements.
- Nuts and seeds. In early studies of the diet, people ate a handful of almonds every day. Other tree nuts, peanuts, and seeds were included in later studies.
"People don't normally put all these foods together," Jenkins says. "People talk about soy, and oat bran, and plant sterols, oils and nuts, but nobody has put them all together."
Don’t worry: Those foods aren’t all going into one dish. They’re spread throughout the day.
A typical day on the portfolio diet offers:
- Breakfast: Soy milk, oat-bran cereal with chopped fruit and almonds, and a blueberry smoothie with Metamucil
- Lunch: Oat-bran bread, bean soup, and an apple
- Dinner: Tofu stir-fry with peanuts and lots of vegetables such as eggplant or okra that are rich in viscous fiber
- Snacks: Choose from items like nuts, crunchy chickpeas, soy yogurt, or oat-bran bread with sterol-enriched margarine and jam.
Does the Portfolio Diet Work?
Jenkins’s team wanted to test the diet in the real world. So they signed up 46 people who said they wanted lower cholesterol, told them what to eat, and gave them sample menus. But they didn't provide any prepared foods.
"Just about a third of them get very good results, with better than a 20% reduction in the 'bad' LDL cholesterol after six months," Jenkins says. "Those results are constant from two weeks to six months. So after two weeks, you can say, 'These are the people who are likely to stay the course.'"
For another 31% of people studied, LDL cholesterol dropped by 15%. But LDL cholesterol levels didn’t budge for the rest of the people in the study. That may be because they weren't able to follow all the rules of the portfolio diet.
"Most people complied with the advice to eat almonds and to substitute plant sterol products for margarine," Jenkins says. "But fewer people were able to use soy milk and soy dogs and tofu instead of meat and dairy. Having said that, people who were fairly robust at being able to whip up something at home tended to do best. Those who relied on packaged goods or had to eat out a lot had much more of a problem."
After that study, published in The Journal of the American Medical Association back in 2003, Jenkins’s team did five observational studies. While that work didn’t directly test the portfolio diet, the observational studies were larger, longer, and more diverse – and also showed benefits.
Looking across all six studies, Jenkins says that the portfolio diet lowers LDL-C by 17%, apolipoprotein B (15%), total cholesterol (12%) and triglycerides (16%). The observational studies showed that people who more closely followed the portfolio diet had a lower risk of heart disease, type 2 diabetes, and even early death. An important finding from these observational studies is that even eating some portfolio diet foods may protect you against several chronic diseases like heart disease, Jenkins notes.
“So even if you start adding just a few portfolio diet foods into your routine, you’ll still have a good return on your investment over the long term,” he says.
There’s a windfall, too. “When you follow the portfolio diet, remember that it also reduces the animal-to-plant-protein ratio, and therefore aims to also be humane and environmentally friendly,” Jenkins says. You can track your progress on the diet, too.
Is the Portfolio Diet Right for You?
"If your goal is cholesterol reduction, this is a very adequate plan," says Richard Milani, MD, chief clinical innovation officer at Sacramento, California-based Sutter Health. "If your goal is weight reduction, this may not be it. If your goal is reducing your risk of heart attack, the Mediterranean diet may be better – although plant sterols and nuts are part of the Mediterranean diet, too."
But Milani is quick to note that the foods in the portfolio diet can be added to almost any healthy diet.
"It can be done – inexpensively – to get people's cholesterol under control,” he says.
Cholesterol-lowering drugs have more side effects at high doses, Jenkins notes. So he suggests that the foods in the portfolio diet may help people get the most out of these drugs – without increasing the dosage.
