High potassium foods reduce blood pressure and improve bone density. Nuts are high potassium food, but also have other contributions to health. They provide healthy fats that reduce cardiovascular disease. A recent review (1) this year discussed how the type of fat in your food can make all the difference in heart disease. Healthy nuts are loaded with polyunsaturated and monounsaturated fats.
When Carbohydrates Replace Saturated Fat
There have been two main approaches to reducing coronary heart disease (CHD). One is to replace saturated fats with carbohydrates. That has been the most popular approach the past 20 or so years. The type of carbohydrate makes a big difference, but that has been ignored in most of the changeover. The U.S. has seen a decrease in death from CHD since 1968, but has also seen a big increase in obesity and diabetes. This is most likely related to the dietary switchover from saturated fat to high caloric density carbohydrates during that time.
When Unsaturated Fat Replaces Saturated Fat
The other approach has been to replace saturated fats with monounsaturated and polyunsaturated fats, such as the fats found in nuts, olive oil and other vegetable oils. This has resulted in a much lower incidence of CHD. Replacing saturated fat with carbohydrates lowers total cholesterol, but keeps the LDL to HDL ratio the same. But by lowering LDL and keeping stable or raising HDL, the ratio improves markedly. This ratio is a much better predictor of CHD than total cholesterol.
Replacing saturated fat with monounsaturated fat lowers LDL. Replacing it with polyunsaturated fat lowers it even more. By replacing red meat with fish or nuts you are replacing saturated fat with mono and polyunsaturated fat and markedly improving your LDL/HDL ratio.
Trans fat is polyunsaturated fat that has been hydrogenated. It is a very unhealthy unsaturated fat. When vegetable oil is heated in metal it produces trans fat. As much as 60% of partially hydrogenated vegetable oil can be trans fat. In your body trans fat does the exact opposite of the fats in nuts. It raises LDL and lowers HDL. And yes, the end result is what you would think – more CHD, much more.
Some of the studies reviewed show that the percentage of calories that comes from fat is unimportant for the development of heart disease, if the fat is the right kind. The 10% or 20% rules come from when Americans were getting mostly saturated fat. Higher percentages have no adverse effect if the fats are poly or monounsaturated.
Omega 6 Or Omega 3
Another myth is the concern about omega 6 versus omega 3 fat. Not all omega 6 and omega 3 fats are the same. One study included 20% of calories coming from polyunsaturated fat that was mostly omega 6. The people in the study still had a marked reduction in CHD.
That is not to say that the exact omega 6 or omega 3 fat is unimportant. It's just that simply classifying a fat as omega 6 or omega 3 does not tell the whole story. What is important is how much the fat lowers CHD. The exact fat eaten is important. A study done in Lyon placed participants on a low fat diet or a Mediterranean diet with a high intake of fat from rapeseed oil, which contains a large amount of ALA (as do walnuts). That group had a 70% reduction in recurrent CHD.
If you want a simple way to lower your blood pressure, a high potassium foods diet will likely do the trick. If you also want to lower your chances of CHD beyond the improvement from lower blood pressure, simply lower the saturated fat intake and include a good amount of healthy nuts, especially walnuts, in one or two meals a day.
For tables showing the potassium content of foods, look here to find the food group you are interested in. A table for nuts is here.
1. Dietary fats and coronary heart disease. Willett WC. J Intern Med. 2012 Jul;272(1):13-24. doi: 10.1111/j.1365-2796.2012.02553.x.