Friday, April 18, 2014

Smoking good for your health? Making sense of the new fat and heart disease study.

It was like waking up in Sleeper, the Woody Allen movie, when the main character, asleep for umpteen years, wakes to find that cigarette smoking is good for your health. That’s how I felt some weeks ago after reading the half page article in the NY Times entitled “Study Questions Fat and Heart Disease Link”, based on the recent study by Dr. Chowdhury et al which reviewed more than 70 scientific studies and appears to turn our cholesterol lowering guidelines on its head.

No one is concluding you should be eating more of this.
You, my readers, may have little concern about your heart disease risk. Yet I urge you to keep reading—because unless this news splash is explained, you’ll be left feeling like health professionals just can’t get it right. I mean, one day they say saturated fats are bad, and next day they tell you they don’t impact your risk. Carbs are good, and then they’re bad. Hormone replacement therapy is recommended, and then it’s dangerous. Confronted with so much conflicting information, you, like me, might decide to trust none of it. And health professionals end up looking like a bunch of clowns.

After a deep breath, I poked through the research and sorted through the recommendations. And here’s how I’ve made sense of it so far:

  • Saturated fat increases blood cholesterol levels, including LDL, the so-called ‘bad’ cholesterol. Yes, that’s still true.
  • LDL does increase heart disease risk. Yup, still the case.
  • But reducing saturated fat doesn’t appear to lower heart disease.

So why doesn’t reducing saturated (sat) fat appear to improve risk? There are a few explanations:

Cornbread from Food to Eat and Drop the Diet
fits in a balanced diet!

  • Because most studies reducing sat fat reduced all fat. And when you reduce all fat something has to fill the void. Our food supply has three main building blocks—protein, carbohydrate and fats. Dramatically reduce one, something else fills the void, as a percentage of total calories. Generally, carbohydrate-rich foods replaced saturated fats in our diets. And the increased carbs tend to come from convenient, more processed, low fiber choices. Now let me clarify—those foods, themselves, as part of a balanced diet, don’t cause disease! But substituting saturated fat with a large intake of these items—rather than, let’s say foods rich in non-saturated fats (think nuts, avocado/guacamole, olive oil) raises another blood fat called triglycerides. And triglycerides increase heart disease risk. So in an effort to do something positive, namely reduce saturated fat to lower LDL/bad cholesterol, we’ve been increasing triglyceride levels. It’s like thinking that eating fat free Snackwell cookies instead of Oreos will make you healthier.
  • Harvard professors Willett, Sacks and Stampfer highlight several problems with Chodhury’s study. It fails to point out that substituting polyunsaturated fat for sat fat was associated with lower risk of heart disease. And the monounsaturated fats we usually think about as the healthy ones-those from avocado, nuts and olive oil, for instance—were not the sources referred to when concluding no health benefit from monounsaturated fats. 
  • When we combine lots of studies, the summary of the data may block out the small but critical findings. For instance, the authors conclude that  "Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats." And that is surely what the media jumped on. But the truth is that certain unsaturated fats did result in benefits. Specifically, the active components in fatty fish, the omega 3s EPA and DHA were clearly shown to be protective. It's well established that these fatty acids lower triglyceride levels, decrease clot formation, decrease inflammation and act as a blood thinner, among other functions. 
Don't let fatty fish scare you!
Check out our curry salmon recipe in Food to Eat.
  • Supplementing with omega 3 fats had no benefit in Chodhury’s study. But here’s what I’d wonder: how consistent were supplementers with taking their supplements? Were doses at levels that really make a difference (most people mistake total omega 3s for the active EPA and DHA we’re looking to boost), and were those supplement takers already at higher risk—like maybe people who had already had heart attacks? Perhaps increasing food sources of omega 3 fatty acids (think salmon, tuna, bluefish, sardines, for instance), displaced saturated fat from other common protein sources, such as beef, pork and poultry, showing that food sources have more impact than simply supplements. Just a thought.
  • Lumping saturated fats as a single category misses the differences of various types of saturated fats. Saturated fat from dairy fat, for instance, was not viewed as a bad fat; it was associated with lower cardiovascular risk (perhaps it’s time to skip the low fat cheese and enjoy the good stuff!). So if you combine a bunch of studies with different sources of saturated fats with varying benefits and risks for heart disease, it waters down the results. As this study concludes, saturated fats (AS A WHOLE GROUP) may not be the issue, but certain types remain a concern.

Where do we go from here?

Can't go wrong with my favorite wheatberry salad, made with 
whole grains,a bit of sweetness and heart healthy oil and nuts.
First, let's focus on foods, not just nutrients. To me what’s most practical is to learn from the diets of populations which have lower(ed their) risk of heart disease. This Circulation article demonstrates the benefits of a Mediterranean style diet on not just lowering cholesterol values, but significantly reducing heart disease risk—so much so, that the study had to be stopped early, given the 50-70% lower risk of recurrence. “These study subjects adopted a Mediterranean-type diet that contained more bread, more root vegetables and green vegetables, more fish, fruit at least once daily, less red meat (replaced with poultry), and margarine supplied by the study to replace butter and cream.”  Use of various oils were recommended, but not limited to olive oil, and moderate alcohol was also included.

And then there was the diet in Crete which is quite similar—full of fresh and dried fruits, grains and cereals, daily dairy, poultry and fish only weekly and red meat rarely. Oil was the predominant fat and oh, the Cretans ate desserts—and not just fruit, but pastry made with honey, too--a few times weekly!

Yes, balance.
Nope, the healthiest people were not eating low carb, nor gluten free. There was no almond milk nor fear of dairy. And fats and desserts still had a role in this most healthy way of life.

My conclusion? We should focus more on eating a balanced diet rich in a range of nutrients. Yes, back to the basics you may now fear—grains and cereals (whole grains are best), nuts and oils, fruits and vegetables and fish, including fatty types and lean meats and poultry to fill the void. Include dairy, not limited to the lowest fat ones you can stomach.

And remember there’s a place for wine and desserts, in moderation.

No comments:

Post a Comment