David Jenkins is a Toronto-based clinician scientist at the forefront of nutrition research in Canada and across the globe. He is credited with the development of the glycemic index in the 1980s and in the early 2000s his novel research venture led to the identification of a specific dietary pattern that helps reduce “bad” cholesterol (LDL) levels. He referred to the pattern as a Dietary Portfolio, although many people know it as the Portfolio Diet. Today’s article serves both as recoqnition of Dr. Jenkin’s work in the field of nutrition as well as a thorough review of the components of his cholesterol lowering eating plan.
The Portfolio Diet is of particular significance to me because, as an undergraduate student, a classmate and I explored how one could incorporate the Portfolio Diet into their daily lives in order to lower their LDL cholesterol levels. It was a thoroughly enjoyable experience and I am thrilled to be able to re-visit it here. Let’s now explore why Dr. Jenkin’s work on dietary cholesterol reduction is so important and identify the foods that are central to this effect.
Higher than normal LDL (bad cholesterol) levels are an important risk factor for heart disease and overall health. Simply put, the lower you can get your LDL cholesterol, the better. Dietary modification and/or medication are the two primary methods for cholesterol lowering. Depending on the severity of your cholesterol levels, and your other cardiovascular risk factors, your doctor may suggest you try one or both of these approaches. Dr. Jenkin’s research found that a specific group of foods , consumed together, had the potential to significantly reduce an individual’s cholesterol levels.
Introducing The Dietary Portfolio/Portfolio Diet
i) Tree Nuts: Tree nuts include foods such as almonds, pecans and walnuts. The portfolio diet calls for about 45 grams of tree nuts daily for an average 2,000 calorie diet. This amounts to about 37 almonds a day. I recommend incorporating tree nuts with a fruit as either a healthy breakfast or snack item. (I believe that tree nuts and fruit are the ultimate healthy snack)
ii) Enriched Plant Sterol Margarine: There is a reasonable chance that you have either already heard of this product or encountered it on your local grocery store shelves. If not, look for Becel Proactiv Margarine or PC Blue Menu Margarine with plant sterols. The Portfolio Diet calls for 2 grams of plant sterols a day for an average 2,000 calorie diet. This amounts to about 2 tablespoons of enriched plant sterol margarine which could be incorporated in the usual ways you would enjoy margarine, such as spreading it on toast.
iii) Soy Protein: Soy Protein can be found in soy beverages, tofu and textured vegetable protein products such as soy-based meat alternatives. The portfolio diet calls for about 50 grams of soy protein a day in an average 2,000 calorie diet. Regularly consuming multiple soy protein-rich items daily will help you reach this number. Specific examples of soy protein-rich foods include items such as tofu, tempeh, soy milk/yogurt, edamame (soy beans) and veggie burgers/soy meat alternatives. Soy milk and yogurt are natural replacements for dairy in the portfolio diet. ( Curious? Read more about the benefits & challenges associated with choosing plant-based products over meat & dairy)
iv) Soluble Fibre: Soluble fibre is a specific type of dietary fibre that can help lower your cholesterol levels. It is quite likely that you are currently not consuming soluble fibre at the levels suggested by the Portfolio Diet. The eating pattern calls for around 20 grams of soluble fibre a day for an average 2,000 calorie diet. The foods described below contain between 1 to 3 grams of soluble fibre per listed serving size:
Grains: Cooked Oatmeal or Barley (1/2 cup), Bran Buds (1/3 cup).
Fruit: Pear, Orange, Apple, Peach, Banana – 1 medium fruit.
Vegetables: Broccoli, Brussel sprouts, Eggplant, Carrots, Okra – 1/2 cup.
Legumes: Lima beans, Kidney Beans, Black Beans, Navy Beans, Lentils – 1/2 cup.
v) Legumes: The portfolio diet recommends using legumes ( lentils, beans, peas) in place of meat/eggs/poultry/fish whenever possible. Legumes are an excellent protein alternative and also contain soluble fibre that will help you reach the Portfolio Diet’s soluble fibre recommendations.
Depending on how closely you are able to follow these guidelines, the portfolio diet has the potential to lower your cholesterol by over 20%. If you do a reasonable job of following the dietary pattern, you may be looking at closer to a 10-20% reduction. Consistency and regularity in consuming these foods is critical to maintaining an optimal cholesterol lowering effect. I also appreciate that one of the limitations of this dietary pattern is that it includes several alternative food items that may not be regularly consumed, or that may be hard to consume on a consistent basis. As a result, the portfolio diet can be difficult to commit to in the long-term. Do keep in mind that each of the individual components of the diet have their own unique cholesterol lowering potential, which means that you do not necessarily need to follow the diet perfectly to experience a cholesterol lowering effect. However, the more closely you follow the dietary pattern, the greater cholesterol lowering effect you are likely to experience.
Individuals who prepare their own meals and eat at home more often are more likely to have success following this dietary pattern. With that being said, the Portfolio Diet is not the only way to reduce your cholesterol levels through dietary means. The Portfolio Diet is one of three eating styles currently recommended by the Canadian Cardiovascular Society for reducing elevated LDL cholesterol levels and/or reducing cardiovascular risk. The other eating patterns in this category include the DASH and mediterranean diets. Those who feel the Portfolio Diet is not the right fit for them would be well served to further research each of those eating patterns. As always, I wish you the best of luck on your healthy eating journey and would just like to remind you to be proud of the fact that the portfolio diet was developed in Canada!
Until next time, Eat Up!
Andy De Santis RD MPH