Nonlinearity and the industrial seed oils paradox

Most relationships among variables in nature are nonlinear, frequently taking the form of a J curve. The figure below illustrates this type of curve. In this illustration, the horizontal axis measures the amount of time an individual spends consuming a given dose (high) of a substance daily. The vertical axis measures a certain disease marker – e.g., a marker of systemic inflammation, such as levels of circulating tumor necrosis factor (TNF). This is just one of many measurement schemes that may lead to a J curve.

J-curve relationships and variants such as U-curve and inverted J-curve relationships are ubiquitous, and may occur due to many reasons. For example, a J curve like the one above may be due to the substance being consumed having at least one health-promoting attribute, and at least one health-impairing attribute. The latter has a delayed effect, and ends up overcoming the benefits of the former over time. In this sense, there is no “sweet spot”. People are better off not consuming the substance at all. They should look for other sources of the health-promoting factors.

So what does this have to do with industrial seed oils, like safflower and corn oil?

If you take a look at the research literature on the effects of industrial seed oils, you’ll find something interesting and rather paradoxical. Several studies show benefits, whereas several others hint at serious problems. The problems seem to be generally related to long-term consumption, and to be associated with a significant increase in the ratio of dietary omega-6 to omega-3 fats; this increase appears to lead to systemic inflammation. The benefits seem to be generally related to short-term consumption.

But what leads to the left side of the J curve, the health-promoting effects of industrial seed oils, usually seen in short-term studies?

It is very likely vitamin E, which is considered, apparently correctly, to be one of the most powerful antioxidants in nature. Oxidative stress is strongly associated with systemic inflammation. Seed oils are by far the richest sources of vitamin E around, in the form of both γ-Tocopherol and α-Tocopherol. Other good sources, with much less gram-adjusted omega-6 content, are what we generally refer to as “nuts”. And, there are many, many substances other than vitamin E that have powerful antioxidant properties.

Chris Masterjohn has talked about seed oils and vitamin E before, making a similar point (see here, and here). I acknowledged this contribution by Chris before; for example, in my June 2011 interview with Jimmy Moore. In fact, Chris has gone further and also argued that the vitamin E requirement goes up as body fat omega-6 content increases over time (see comments under this post, in addition to the links provided above).

If this is correct, I would speculate that it may create a vicious feedback-loop cycle, as the increased vitamin E requirement may lead to increased hunger for foods rich in vitamin E. For someone already consuming a diet rich in seed oils, this may drive a subconscious compulsion to add more seed oils to dishes. Not good!

Nuts by numbers: Should you eat them, and how much?

Nuts are generally seen as good sources of protein and magnesium. The latter plays a number of roles in the human body, and is considered critical for bone health. Nuts are also believed to be good sources of vitamin E. While there is a lot of debate about vitamin E’s role in health, it is considered by many to be a powerful antioxidant. Other than in nuts, vitamin E is not easily found in foods other than seeds and seed oils.

Some of the foods that we call nuts are actually seeds; others are legumes. For simplification, in this post I am calling nuts those foods that are generally protected by shells (some harder than others). This protective layer is what makes most people call them nuts.

Let us see how different nuts stack up against each other in terms of key nutrients. The quantities listed below are per 1 oz (28 g), and are based on data from Nutritiondata.com. All are raw. Roasting tends to reduce the vitamin content of nuts, often by half, and has little effect on the mineral content. Protein and fat content are also reduced, but not as much as the vitamin content.

These two figures show the protein, fat, and carbohydrate content of nuts (on the left); and the omega-6 and omega-3 fat content (on the right).

When we talk about nuts, walnuts are frequently presented in a very positive light. The reason normally given is that walnuts have a high omega-3 content; the plant form of omega-3, alpha-linolenic acid (ALA). That is true. But look at the large amount of omega-6 in walnuts. The difference between the omega-6 and omega-3 content in walnuts is about 8 g! And this is in only 1 oz of walnuts. That is 8 g of pro-inflammatory omega-6 fats to be “neutralized”. It would take many fish oil softgels to achieve that.

Walnuts should be eaten in moderation. Most studies looking at the health effects of nuts, including walnuts, show positive results in short-term interventions. But they usually involve moderate consumption, often of 1 oz per day. Eat several ounces of walnuts every day, and you are entering industrial see oil territory in terms of omega-6 fats consumption. Maybe other nutrients in walnuts have protective effects, but still, this looks like dangerous territory; “diseases of civilization” territory.

A side note. Focusing too much on the omega-6 to omega-3 ratio of individual foods can be quite misleading. The reason is that a food with a very small amount of omega-6 (e.g., 50 mg) but close to zero omega-3 will have a very high ratio. (Any number divided by zero yields infinity.) Yet, that food will contribute little omega-6 to a person’s diet. It is the ratio at the end of the day that matters, when all foods that have been eaten are considered.

The figures below show the magnesium content of nuts (on the left); and the vitamin E content (on the right).

Let us say that you are looking for the best combination of protein, magnesium, and vitamin E. And you also want to limit your intake of omega-6 fats, which is a very wise thing to do. Then what is the best choice? It looks like it is almonds. And even they should be eaten in small amounts, as 1 oz has more than 3 g of omega-6 fats.

Macadamia nuts don’t have much omega-6; their fats are mostly monounsaturated, which are very good. Their protein to fat ratio is very low, and they don’t have much magnesium or vitamin E. Coconuts (i.e., their meat) have mostly medium-chain saturated fats, which are also very good. Coconuts have little protein, magnesium, and vitamin E. If you want to increase your intake of healthy fats, both macadamia nuts and coconuts are good choices, with macadamia nuts providing about 3 times more fat.

There are many other dietary sources of magnesium around. In fact, magnesium is found in many foods. Examples are, in approximate descending order of content: salmon, spinach, sardine, cod, halibut, banana, white potato, sweet potato, beef, chicken, pork, liver, and cabbage. This is by no means a comprehensive list.

As for vitamin E, it likes to hide in seeds. While it may be a powerful antioxidant, I wonder whether Mother Nature really had it “in mind” as she tinkered with our DNA for the last few million years.