Does What You Eat Affect Inflammation?

You have probably heard claims about diets that can reduce inflammation throughout the body and ease the symptoms of arthritis. But do they work? Scientists have found evidence that the body’s level of inflammation is related in part to what we eat. They have even identified some compounds in foods that can reduce inflammation and others that promote it. But we still have a lot to learn about how diet and inflammation interact, and research is not yet at the point where specific foods or groups of foods can be singled out as especially beneficial for people with arthritis. Nevertheless, we are beginning to get a clearer picture of how eating the right way can reduce inflammation.

Inflammation 101

Why are we so concerned about inflammation? Inflammation is the body’s natural response to infection and injury. When something goes wrong — say, a virus enters your body or you cut your finger — the body’s immune system works to inflame the area, which serves (if all goes well) to trounce the invader or heal the wound. Inflammation can cause pain, swelling, redness, and warmth, but these all go away when the problem resolves. This is the good type of inflammation.

Then there’s chronic inflammation — the type that’s familiar to people with rheumatoid arthritis (RA), lupus, psoriatic arthritis, and other types of “inflammatory” arthritis. Chronic inflammation is inflammation that doesn’t go away. In the above-mentioned types of arthritis, a disordered immune system creates inflammation and then doesn’t know when to shut it off. In inflammatory arthritis, chronic inflammation can have serious consequences. If not treated properly, it can end up damaging the body’s tissues and causing permanent disability.

Inflammation has also been implicated in a whole host of other medical conditions. For example, inflammation contributes to atherosclerosis, in which fat builds up on the lining of arteries, raising the risk of heart attacks. Indeed, high levels of inflammatory proteins have been found in the blood of people with heart disease. Inflammation has also been linked to obesity, diabetes, asthma, depression, and even Alzheimer disease and cancer. Scientists think that a constant level of inflammation in the body — even if the level is low — can have many negative effects. Since research shows that diet can reduce inflammation, in theory an inflammation-lowering diet should have an effect on a wide range of health conditions.

Inflammation and food

To discover which foods might benefit us the most, researchers have looked for clues in the eating habits of our early ancestors. Those habits, they believe, are more in tune than modern eating habits with how the body processes and uses what we eat and drink.

Built to be a hunter-gatherer? A lot has changed since the days in which our ancestors were hunter-gatherers and subsisted on a diet of wild lean meats (such as venison or boar) and wild plants (such as green leafy vegetables, fruits, nuts, and berries). There were no cereal grains until the dawn of the agricultural revolution (about 10,000 years ago). There was also little dairy, and of course there were no processed or refined foods. And whatever hunter-gatherers ate, they first had to hunt or otherwise track down.

Today, our diets are typically high in meat, saturated (or “bad”) fat, and processed foods, and our lifestyles are largely sedentary. Furthermore, nearly all of our food needs (and then some) are available close by or even at the click of a mouse. Many believe that our diet and lifestyle are way out of tune with how the body is made from the inside out.

While our genetic make-up has changed very little since our hunter-gatherer days, our diet and lifestyle have changed immensely, and the changes have accelerated over the last 50 or 100 years. Our genes have not had time to adapt. This is the crux of the matter. We aren’t giving our bodies the right kind of fuel — it’s as though we think they are like engines in jet planes when instead they’re like engines in the very first airplanes. Some of the foods we are putting in our bodies, particularly because we are eating too much of them, are affecting our health.

Omega-3’s and omega-6’s. Two nutrients in our diet that have attracted particular attention are omega-3 fatty acids and omega-6 fatty acids. Fatty acids are the building blocks of fat. Omega-3 and omega-6 fatty acids have been part of our diets for thousands of years. They are components in practically all our trillions of cells and are important for normal growth and development. Both of these fatty acids play a role in inflammation. Several studies have shown that certain sources of omega-3’s in particular help to dampen the inflammatory process, while omega-6’s excite it.

Here’s the problem: The average American eats about 15 times more omega-6’s than omega-3’s. This is a totally new phenomenon for the human body. Our hunter-gatherer ancestors ate omega-3’s and omega-6’s at about an equal ratio. This is believed to have helped balance their ability to turn inflammation on and off. The imbalance of omega-3’s and omega-6’s in the modern diet is thought to contribute to excess inflammation in the body.

Why do we eat so many omega-6’s today? Vegetable oils such as corn oil, safflower oil, sunflower oil, cottonseed oil, soybean oil, and their products, such as margarine, are rich in omega-6’s. Many of the processed snack foods so prevalent today are also chock full of these oils. Plus, the old recommendation, based on the best information available at the time, was to use vegetable oils like those above instead of foods with saturated fats such as butter and lard. This advice may have inadvertently contributed to an increased intake of omega-6’s and to an upset in the balance of omega-3 and omega-6 consumption.

Omega-6’s are also found in other common foods such as meats and egg yolks. The type of omega-6 fatty acid found in meat is most highly concentrated in meat from grain-fed animals such as cows, lambs, pigs, and chickens. (Most meat sold in the United States is grain-fed.) Their grass-fed counterparts contain less of it. Interestingly, wild game meat, such as venison and boar, is also lower in omega-6’s and fat and higher in omega-3’s than the domesticated meat we get from the supermarket.

Omega-3 fatty acids are found in both animal and plant foods. The body converts omega-3’s from animal sources into anti-inflammatory compounds more efficiently than it converts omega-3’s from plant sources. But don’t discount plant foods. They contain hundreds of other healthful compounds, many of which are also anti-inflammatory.

Animal foods high in omega-3’s include fatty fish — especially coldwater species, such as salmon and mackerel (with wild fish seeming to be better sources than farm-raised). Anchovies, sardines, herring, striped bass, and bluefish are good sources too. You can also buy eggs enriched with omega-3 oil. Excellent plant sources of omega-3’s include leafy greens (such as kale, Swiss chard, and spinach) as well as flaxseed, wheat germ, walnuts, and their oils.

Omega-3’s are also available as supplements (often as fish oil), which have been shown to be beneficial in some instances. (See “Arthritis and diet” below.) However, you should talk to a health-care professional before taking a fish oil supplement as it can interact with some medicines and under certain circumstances can increase the risk of bleeding.

Other fats. Saturated fats found in meats and high-fat dairy foods, which are often labeled as “bad” fats because they contribute to clogged arteries, are also pro-inflammatory. In addition, there are the trans fats, those relatively new villains of heart health. They are found in processed, convenience, and snack foods and can be identified on labels as partially hydrogenated oils, often soybean oil or cottonseed oil. They also occur naturally in small amounts in animal foods. They are thought to contribute to pro-inflammatory activities in the body, and in the amounts we consume today they were strangers to our hunter-gatherer ancestors.

Antioxidants. Antioxidants are substances that prevent inflammation-causing “free radicals” from becoming too prevalent in our bodies. Antioxidants are found in high amounts in plant foods such as fruits, vegetables (including beans), nuts, and seeds. Extra-virgin olive oil and walnut oil are also good sources of antioxidants. These foods have long been considered universal pillars of good health. Be on the lookout for fruits and vegetables with colorful and vibrant pigments. The more colorful the plant, the better, from green vegetables, especially leafy ones, to low-starch vegetables, such as broccoli and cauliflower, to berries, tomatoes, and brightly colored orange and yellow fruits and vegetables.

Arthritis and diet

So what does all of this have to do with arthritis? There has been some research on diet and arthritis, most of it focusing on RA. For example, a study that looked at a pool of studies on diet and RA found that diets high in omega-3’s had some effect on reducing the symptoms of RA. Another study, published in 2008, found that eating omega-6 fatty acids and omega-3 fatty acids in a ratio of 2 or 3 to 1 (a low ratio compared to the 15 to 1 ratio in most people’s diets) decreased inflammation in people with RA. Still other studies have found evidence that omega-3’s from fish sources may reduce morning stiffness and the number of tender joints in people with RA, and other studies have found that taking omega-3 supplements may also allow people to reduce their doses of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, Motrin) and naproxen (Aleve). However, these and similar studies do not offer enough evidence to prove that any particular anti-inflammatory diet can have a real impact on arthritis symptoms. That does not mean that the diets are harmful; on the contrary, research may one day prove their benefit. In the future, diet may be considered one of many tools, along with exercise and medicine, that can be used to ease the symptoms of arthritis.

Following the anti-inflammatory diet

If we want to eat the anti-inflammatory way, we do not have to revert completely to a caveman or hunter-gatherer lifestyle to benefit. The current recommendations for eating a healthful diet are generally on the right track. The chief strategy should be to balance our intake of modern-day foods with our ancestors’ diet, which was rich in inflammation-reducing foods. One key is to replace foods rich in omega-6 with foods rich in omega-3. Cutting down on meat and poultry while eating oily fish a couple of times a week and feasting on a wide variety of vibrantly colored fruits and vegetables are also top priorities. In addition, although this was not a part of the caveman’s diet, you should highlight whole rather than refined grains. They contain many beneficial nutrients and inflammation-tempering compounds. Researchers have also learned that eating a lot of foods high in sugar and white flour may promote inflammation, although more study is needed.

Some cautions

Our knowledge of how the human body is built and of how our ancestors ate helps confirm the old adage: “You are what you eat.” However, we do not have all the information we need to prescribe any particular anti-inflammatory diet. The benefit of an anti-inflammatory diet may depend upon the severity of your health condition and your genetic makeup. Each of us is unique, and it is doubtful that there will ever be one diet that fits us all.

Furthermore, what we eat or don’t eat is just part of the story. Our ancestors were much more physically active than most of us. Physical activity has its own anti-inflammatory effects. Our ancestors were also on the lean side. Body fat is active tissue that can make inflammation-producing compounds.

For the most part, the anti-inflammatory eating style is not sensational, not spectacular or sexy, and definitely not foreign or unusual. You will find many variations or twists to it depending on the source you read. But in essence, it is a way of selecting foods that are more aligned with what the body actually needs. By going back to our roots — our genetic roots, that is — we can achieve a more balanced diet and, we hope, help our bodies be at their best.

Bonnie Bruce is a Senior Research Scientist in the Division of Immunology and Rheumatology in the Department of Medicine at Stanford University.

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