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Omega-6 fats: Have they gotten a bad rap?

I don't know how much of this has percolated through to the mainstream media, but lately I've noticed quite a few articles and editorials directed at medical and nutrition professionals arguing that omega-6 fats have been unfairly maligned.

Out of balance

The idea that has taken hold in the popular consciousness is that we need to eat more omega-3 fats and less omega-6.  It's often pointed out that our ancestral (hunter/gatherer) diet provided roughly equal amounts of these two essential fatty acids and that the modern (post-agriculture) diet provides ten to twenty times as much omega-6 as omega-3.  This imbalance is thought to promote low-level systemic inflammation and hasten aging and disease.

We can address the imbalance by eating more omega-3 (found in fish, flax, hemp) and/or by consuming less omega-6 (found in vegetable oils and processed foods made with them).

But eating less of something is never as popular as eating more of something--or better yet, simply popping a pill that lets you continue eating whatever you want.  So, who wins here? Primarily, people who sell fish oil and other omega-3 supplements.  (See also this recent post on fish oil supplements and their impact on the environment.)

Defending Omega-6 fats

But someone (perhaps vegetable oil manufacturers?) seems to think that people are being needlessly alarmed about omega-6 fats. Thus, the rash of recent articles arguing that omega-6 fats are not the problem--in fact, they promote good health.

What's the evidence for this? Well, for example, it's been pointed out that people who eat more omega-6 fats have lower incidence of heart disease than those who eat less, and that increasing the omega-6 intake can have a favorable effect on cholesterol levels.

But let's take a closer look. It turns out that:

• Omega-6 fats improved the total-to-HDL cholesterol ratio when they are consumed instead of carbohydrates.

• Omega-6 fats reduced LDL cholesterol  and heart disease risk when they are consumed instead of saturated fat.

So, what's actually at work here? Are these folks healthier because they ate more omega-6 or because they reduced their intake of carbohydrates and saturated fat?  Frankly, I think the most that can be concluded here is that omega-6 fats might be less damaging to your heart than carbohydrates and/or saturated fat. But I certainly wouldn't go looking for ways to increase my omega-6 intake based on this research.

My recommendations--pending further data

I am still convinced that improving the ratio of omega-3 to omega-6 fats is a good idea. For the vast majority of us, this means increasing our intake of omega-3s and/or decreasing omega-6.   Note: A small amount of omega-6 is essential for health but you'd have to be eating close to a fat-free diet to be at risk of omega-6 deficiency.

Reducing refined carbohydrates or saturated fat may also improve your health. But I'd suggest you replace those calories with monounsaturated fats (such as those in olive oil) rather than vegetable oils. Unlike omega-6, which has only been shown to be LESS HARMFUL, monounsaturated fats have actually been shown to be BENEFICIAL.

Your thoughts?

Ask Monica: If I'm restricting carbs, do I need to restrict fruits and vegetables?

Q. I've read that you need to restrict carbs and calories in any diet attempt. However, I've also read that one should consume lots of fruits and veggies, both of which are primarily carbs. What do I do?

A. First, let me point out that although restricting carbohydrates is a popular (and effective) approach to weight loss, it is not the only way to lose weight.  The only thing needed for a successful weight loss program is to consume fewer calories than you use.  You can cut calories by restricting carbs or fats--or simply by eating a little less of everything.

But, back to the root of your question:  are the carbs in fruits and vegetables unhealthy? No!  You're absolutely correct that fruits and vegetables are close to 100% carbohydrates. However, the amount of carbohydrate per serving is quite small--particularly for vegetables (other than potatoes and corn).

Carb-restricted diets

When most people talk about restricting "carbs," they're really talking about refined carbohydrates. This includes breads, pasta, pastry, sodas, and anything else made with flour and/or sugar. These foods are generally low in nutrients and often provide a lot of empty calories, so cutting down on them makes good sense if you're trying to lose weight. Too many refined carbohydrates can also increase your risk of Type 2 diabetes and heart disease, so cutting back is also a good way to make your diet healthier, even if you don't need to lose weight.

The more extreme forms of carbohydrate restriction also restrict whole grains like brown rice and oatmeal and starchy vegetables like corn and potatoes. While I personally don't think you need to eliminate all grains and starchy vegetables in order to be healthy, I also don't think these foods are necessary from a nutritional point of view.  (Although you do have to be somewhat thoughtful about what you replace them with!)

Eat as many vegetables as you like

Most fruit contains a lot of natural sugars (along with plenty of nutrition). Although the amount of sugar and carbs in whole fruit is low compared with refined carbohydrates, it might be a good idea to limit your intake of fruit to 2 to 4 servings a day. Dried fruit and fruit juices are very concentrated sources of sugar and calories and I often advise people to avoid them when dieting. 

But any diet theory that instructs you to restrict vegetables because they contain carbohydrates is highly suspect.  With the exception of corn and potatoes, vegetables are extremely low in calories and carbohydrates and packed with fiber and nutrients. As far as I'm concerned, eat as much of these as you like!

Cardio fitness DOES still matter!

Have you noticed a bit of a backlash against cardiovascular exercise lately? The Cardio Free Diet, by Jim Karas, is a good example. The author argues that toiling away on a treadmill or stationary bike is the least efficient way to lose weight.

I agree. In terms of burning fat and calories, you get more bang from your buck by spending that time on moderate- to high-intensity strength training.

However, cardiovascular fitness is still important. 

Although it may not be the shortest path to a sleek and toned physique, maintaining a moderate to high level of cardiovascular fitness slashes your risk of heart disease and increases your life expectancy, as reiterated by this latest report.

The authors of this review pooled data from a number of large studies and found that people with maximum aerobic capacity of 7.8 METs or more had a substantially lower rates of heart disease and death from any cause.

Want to see how fit you are?

All you need is  a track or other accurately measured one-mile route and a stopwatch. Time how fast you can walk (not run!) a mile and take your pulse as soon as you finish. Then, plug your numbers into this calculator to estimate your aerobic fitness in both VO2max and METs.  (See the calculator for more complete instructions.)

If you find that your cardiovascular fitness is low, it's time to add a little cardio back into the exercise routine.  But you don't need to log countless hours or miles on the stairmaster.  Our fitness guru Steve Cabral explains the basics of interval training, which is the best (and fastest) way to increase your aerobic fitness level.

Chew better, stay full longer?

Almonds have a reputation for being a filling--yet nutritious--snack. Rich in monounsaturated fats, fiber, and protein, a small handful of almonds can take you a long way before the hunger meter hits "empty" again.

But if you're using almonds as a weight-loss or hunger-control strategy, here's an important piece of the puzzle. Chewing your almonds thoroughly will keep you feeling fuller longer!A small study found that those who chewed an ounce and a half of almonds 40 times felt more full than those who chewed them only 10 or 25 times. Blood tests confirmed higher levels of appetite-suppressing hormones in the chewers' blood.

Chewing more thoroughly is a tried-and-true dieting strategy. It definitely slows you down, and that alone could have beneficial effects on moderating your total food consumption. Better appetite control would be a bonus!

Now, I'm wondering if chewing other foods more thoroughly would have similar effects?

Study: Gluten-free diet decreases beneficial bacteria in gut

The headline of this study caught my eye: Gluten-free diet not friendly to gut bacteria.  People with celiac disease (and increasingly, many others) avoid wheat and other sources of the protein gluten. This study showed that after following a gluten-free diet for a month, subjects had fewer beneficial bacteria in their intestines. At first glance, this would suggest that a gluten-free diet might have unintended consequences on intestinal health and immunity.

Reading further, however, I ended up with more questions than answers. First, the study only involved ten people--a very small group. The study was also done on healthy volunteers. People with celiac disease might (indeed, probably) would experience different results because their guts are very different from healthy guts. I also think it somewhat likely that going off gluten could cause a temporary decrease in beneficial bacteria. As your system adjusts, I wouldn't be surprised if the gut flora rebounded.

But this is still a very interesting finding and I hope more research will be done.  In the meantime, if I were following a gluten-free diet, I might be motivated to add more fermented foods (such as yogurt) to my diet in an effort to keep my gut colonized with the right stuff.

Thoughts?

Tips and recipes for a healthier Memorial Day cookout

This weekend is the traditional opening of the summer grilling season (although we pretty much grill year-round at my house, snow or no!).  Grilling is a quick, convenient, and delicious way to prepare many foods. However, grilling also presents a health risk. Two separate types of carcinogenic compounds are produced by high-temperature grilling:

• heterocyclic amines (HCAs)
  HCAs form when a meat is directly exposed to a flame or very high-temperature surface. The creatine-rich meat juices react with the heat to form various HCAs, which have been shown to cause DNA mutation, and may be a factor in the development of certain cancers.
• polycyclic aromatic hydrocarbons (PAHs)
  PAHs form in smoke that's produced when fat from the meat ignites or drips on the hot coals of the grill. Various PAHs present in the resulting smoke adhere to the outside surface of the grilled meat. PAH exposure is also believed to be linked to certain cancers.

Here are some tips for dramatically reducing HCA and PAH content in grilled meats:

1. Select leaner meats.
   Leaner cuts of meat are less likely to drip fat on the grill and produce PAH-laden smoke.
2. Marinate meats before grilling.
   Researchers have determined that marinating meat prior to grilling, even for just a few minutes, can reduce HCA formation by 90% or more.
3. Grill at lower temperatures.
   Lower temperature "roasting" also greatly reduces HCA formation.
4. Prevent flare-ups.
   Flames from grill flare-ups cause the formation of both HCAs and PAHs. Keep an eye on your grill and turn meats frequently to minimize the chance of flare-ups.
5. Don't overcook meats.
   While it's important to cook poultry and ground meats thoroughly, be careful not to overcook any meat. Well-done or burnt meats contain higher levels of HCAs than less cooked meats.

Or, opt for a vegetarian cookout.  HCAs and PAHs are not formed when grilling  and the options are virtually unlimited: Try veggie kabobs, portobella mushrooms, or black bean burgers.

Here are a variety of recipes (both veggie and non) for a healthy, gourmet Memorial Day cookout. (Click on "see nutritional analysis" for a complete ND analysis of each recipe!

Grilled Asian Flank Steak with Sweet Slaw

Yogurt-Marinated Chicken Kebabs

Grilled Shiitakes with Ginger and Scallions

Bulgur Veggie Burgers with Lime Mayonnaise

Spicy Grilled Chicken with Green Onions

Grilled Lemons, Baby Artichokes, and Eggplant

Grilled Pork Loin with Fire-Roasted Pineapple Salsa

Ask Monica: What's a healthy kind of cheese?

Q.  I enjoy making quiche; however, I would like to make it with a healthy type of cheese.  I have been using mild cheddar cheese by Kraft.  Is there a healthy cheese to use? 

A. It depends on what you mean by "healthy"! Cheese contains a fair amount of fat and calories and much of the fat is saturated.  But fat, calories, and saturated fat are only unhealthy if eaten in excessive amounts.

If you are trying to cut fat or calories, some kinds of cheese, such as part-skim mozzarella, feta, and goat cheese, are naturally lower in fat and calories,  (Use our Nutrient Search Tool to find more.) There are also some reduced-fat versions of higher fat cheese (like cheddar) available. Personally, I don't think they taste good enough to eat on their own but you might find them acceptable in your quiche.

Processed imitation cheese products may have less fat but they are so full of chemicals, I'm not sure they could really be considered healthy. (I'm not even sure they should be considered food.) Finally, you could use whatever cheese you think tastes the best and simply cut back on the quantity a bit.

If you are using a store-bought pie crust, however, then I think you might have more to worry about than the cheese in your quiche. Most pre-made pie crusts are made with hydrogenated vegetable oils (shortening) which contain trans fats and there is really no amount of trans fats that could be considered healthy. Look for (or make) pie crusts with no hydrogenated vegetable oils to minimize the trans fats. 

Pie crust also contains lots of calories. So, again, if cutting fat and calories is your goal, consider a  frittata. Frittatas are sort of a cross between an omelette and a crustless quiche and are a household favorite around here.  Once you eliminate the crust--which doesn't have a whole lot going for it nutritionally anyway, you can probably go ahead and enjoy the cheese guilt-free!

Here is a frittata recipe to try (Click on "see nutrition information" for a complete ND analysis):

Spring Pea Frittata

Updated recommendations for calcium and D

Move over, calcium. Vitamin D now seems to be the premiere nutrient in the fight against osteoporosis. It's been the subject of intense research lately and there's a growing consensus in the scientific community that we need to increase the recommended daily intake for this nutrient. At the same time,  mega-dose calcium supplementation seems to be falling from favor.

In response to the latest research findings, the National Osteoporosis Foundation recently updated their recommendations for these two nutrients. According to the new NOF recommendations, adults under age 50 need 1,000 mg of calcium daily, and adults age 50 and over need 1,200 mg of calcium daily.

Don't forget about food as a source of nutrients!

Note that the NOF recommendatations represent the amount that you should get from dietary sources and supplements combined!  For years, women (especially) have been so brow-beaten (by their doctors, by the media, by manufacturers of calcium supplements) about not getting enough calcium that many now take 1500 mg or more a day in supplement form. 

But the average adult already gets around 600-750mg of calcium from her diet.  Another 1500mg in supplement form is clearly overkill. There's no evidence that getting more than the recommended intake does much good--and many worry that excessive calcium may even be detrimental. At the very least, it can be constipating!

You can use our diet tracking tools to see how much calcium your diet provides. Or, use the following rule of thumb to estimate. The average American diet provides about 250mg of calcium a day not counting dairy products.  Each serving of dairy adds another 200mg or so. I suggest that you take only enough supplemental calcium to make up the difference between your diet and the recommendations.

Just to up the ante a notch further, why not make it a goal (especially for your kids) to get at least 75% of your daily requirement from foods? Use our Nutrient Search Tool to find foods high in calcium.

Vitamin D is another story.

For vitamin D, the NOF recommends that adults under age 50 get 400-800 IU daily, and adults age 50 and older get 800 – 1,000 IU.  But average daily intake from foods is a fraction of that. Fortified dairy products are the primary source of vitamin D in the American diet. It is also found in egg yolks, saltwater fish, and liver--and, of course, produced in the skin when you are exposed to direct sunlight (without sunscreen). 

If you read this blog, you know I'm a BIG proponent of getting nutrients from foods rather than supplements but vitamin D is one that is pretty tough to get from foods alone. I personally take 1,000 IU a day as a supplement, especially in the winter when I am not getting much sunlight on my skin.

Antioxidant supplements in the (negative) spotlight again

 This story in yesterday's New York Times was the most emailed item on NYTimes.com: Vitamins Found to Curb Exercise Benefits

To summarize: Moderate intensity exercise creates free radicals in the body. That sounds like a bad thing, but these free radicals appear to stimulate the body's natural antioxidant defenses as well mechanisms that improves glucose sensitivity.  So, the net effect is that exercise reduces free radical stress in the body and helps protect against Type 2 diabetes.

Here's the kicker: Taking vitamin C and E supplements seems to block these positive benefits of exercise.  If you mop up exercise-induced free radicals with supplemental antioxidants, the body's own antioxidant defenses are not activated.

I realize it's just one study but the news on supplements (especially antioxidants) all seems to point in the same direction lately: Nature knows best. Eating antioxidant-rich fruits and vegetables is a great idea but taking concentrated doses of antioxidants as vitamin supplements may actually do more harm than good.

Personally, I hate swallowing pills so I'm glad to be off the hook! Trying to meet your antioxidant needs with foods rather than supplements is also extra motivation to get those five to nine servings of fruits and vegetables everyday.