Beyond the Paleo: Is it Really the Perfect Diet?

There has been explosive interest in the last few years in eating like our ancient, pre-agricultural ancestors:  following a hunter-gatherer pattern that would have been the norm in the Paleolithic Era (the "stone age").  The idea behind this is that agriculture has only been around for about 10,000 years, which is barely a blip on the evolutionary time scale.  Therefore, our genes are still adapted mostly to eating grass-fed meat, eggs, fish, fruits, nuts, and vegetables.  Foods that were introduced with agriculture - especially grains and beans - are harder to digest, and (so the logic goes) may actually contribute to health problems.

With my studies of biology in college, I am all on board the argument of genetic adaptation.  However, I think we need to look at the Paleo Diet critically to determine if it's really the healthiest way to eat.

• Peer-reviewed, published scientific studies about the Paleo Diet (of which there are fewer than ten) have mainly focused on short-term changes in specific parameters, like body weight, blood sugar, and blood cholesterol levels.  While there is definite benefit in these areas, the research has not gone as far as to prove lower risk of chronic disease or mortality (i.e., risk of dying early).
• The complete elimination of grains contradicts many studies that show decreased risk of chronic metabolic diseases.  Last month, Chinese researchers published data on over 367,000 participants, showing decreased all-cause mortality (that is, dying for any reason) with high consumption of fiber-rich whole grains.
• The argument that our genes have not had time to adapt to an agricultural diet ignores some biological nuances.  Sometimes genetic mutations can confer an advantage, and spread quickly -- the best example of this is the ability to produce the lactase enzyme into adulthood, which appeared just a few thousand years ago.  This allowed some populations to survive better than their neighbors, by taking advantage of dairy as a source of nutrition.  Another wrinkle is the relatively new field of epigenetics, which has found that though our genetic code may not change much, certain genes may be "turned on" or "turned off" (biochemically) in response to environmental pressures.  This can happen within a single generation, and the changes can even be passed on to offspring.

The Paleo Diet can serve some important functions.  As a structured system, it is a good way to break our addiction to sugar and refined carbohydrates, which is one of the leading causes of chronic disease.  By eliminating many common foods, the Paleo Diet can also serve as a tool to help identify foods that may be causing inflammatory reactions in the body.  For the long term, however, I still recommend the Mediterranean Diet (including - gasp! - whole grains), which has a mountain of evidence on improved health outcomes and longer lifespan.

Is Your iPad Killing You?

Regular readers and patients know the importance of a good night's sleep to health.  Low quality sleep, and getting fewer than seven hours of sleep per night, have been associated with chronic diseases such as cardiovascular disease, as well as shorter lifespan. Two recent studies highlight some of the hidden thieves of sleep in our modern world.

Researchers at Brigham and Women's Hospital in Boston compared people who read on an iPad screen before bed to those reading a traditional paper book before bed. The study confirmed what has long been suspected: that exposure to a screen decreases sleep quality, shortens the amount of REM sleep, and leads to worse moods and poor productivity the next day. Ideally, you should avoid all light-emitting screens for at least an hour before bedtime.  The main problem seems to be with the blue wavelengths of light, that suppress our body's natural melatonin production. If you really have to read a screen late in the evening, use a physical filter that blocks bluelight, or use free software such as f.lux that achieves the same effect. For Android users, there are several apps available, such as Twilight.

Another problem associated with difficulty sleeping is the presence of intrusive or repetitive thoughts. Interestingly, researchers at Binghamton University have discovered that one of the best way through to cease anxious thoughts is actually to get to bed earlier. Staying up late at night and having a short duration of sleep just aggravate the problem.

It can be a challenge to adjust your habits to get to bed earlier, but it's worthwhile. Maybe you could stop watching those electronic screens late in the evening. If repetitive thoughts are actually preventing you from falling asleep, you could try and herbal sleep aid such as valerian root, or a do-it-yourself behavior modification programs such as SleepStar.

When you sign up for SleepStar, use code PetersND25 for a discount.

Jacob A. Nota, Meredith E. Coles. Duration and Timing of Sleep are Associated with Repetitive Negative Thinking. Cognitive Therapy and Research, 2014; DOI: 10.1007/s10608-014-9651-7

The Skinny on Fat

In the 1970s and 80s, fat was the bad boy of nutrition.  Since then, research has reminded us of so many of the “forgotten” good things about fat -- from the benefits of omega-3 fatty acids, to absorbing our fat-soluble vitamins and beyond.  As research goes on, more facts come to light to dispel our fears of this nutrient.

A few months ago, I reported that a Mediterranean diet rich in olive oil and nuts decreases the risk of cardiovascular disease by 30% compared to a low-fat diet.  Further analysis (1) of the data from this study (the PREDIMED study from Spain) found that the monounsaturated fat-rich Mediterranean diet also decreased diabetes risk by a third.  This is huge:  cardiovascular disease and diabetes are two of the biggest causes of death and morbidity in this country.  Focusing on low glycemic index foods like whole grains, legumes, fruits, and vegetables, as well as losing our fear of healthy fats like extra-virgin olive oil, can spell out huge health benefits.

Furthermore, a meta-analysis (a study of studies) published in the American Journal of Clinical Nutrition in 2010 (2) tore down one of the most sacred cows of nutrition and health research:  the "evil" of saturated fat.  The authors found no association of saturated fat intake with cardiovascular disease or stroke in the best-designed nutritional studies available to date.  This is mind-boggling, since everyone "knows" that chomping on a cheeseburger will instantly make your arteries clog up.  The jury is still out. but it appears that the ratio of unsaturated fat (from sources like olive oil, fish oil, or nuts) to saturated fat is more important than the absolute amount of saturated fat.  Translated into English, this means that at least half of your dietary fat should come from these healthier sources.  One word of caution, though, is that omega-6-rich fats such as vegetable oil might actually be bad for the heart.

As we sort through all of this evidence. it looks like the best recommendations we have to date are:

• Overall, a low-fat diet is not healthier for most people.
• Balance saturated fat intake (meat, dairy, coconut oil) with healthier fats (olive oil, nuts, avocados).
• Use vegetable oils sparingly (canola, corn, peanut oil).
• Do all of this in the context of a varied, fiber-rich, low glycemic index eating pattern, such as the Mediterranean Diet.

1.  Ann Intern Med. 2014;160(1):1-10-10. doi:10.7326/M13-1725
2.  Am J Clin Nutr 2010;91:535–46.

Coffee: Superfood or Death Sentence?

Earlier this year, I outlined some of the amazing health benefits associated with regular coffee consumption.  These include a decrease risk of chronic diseases such as diabetes, Alzheimer's disease, and endometrial cancer; pain reduction as among its benefits too.

Now, new research from the Mayo Clinic (1) makes us pause and reflect on how much is too much of a good thing.  I often hammer that old adage, "all things in moderation;" in this case, moderation appears to be 4 cups of coffee per day.  More than that raises the risk of death for people under age 55.

Researchers looked at data from the Aerobics Center Longitudinal Study, which examined dietary habits and health data from over 43,000 participants over the course of 31 years.  For folks under the age of 55 who drank more than 28 cups of coffee per week, all-cause mortality risk increased by over 50% for men, and more than doubled for women.  The direct cause of this association is unknown, but seems to be unrelated to coffees cardiovascular effects.

One of the important points to keep in mind is that a "cup" in this study is defined as 8 fluid ounces; the cutoff point therefore seems to be about 32 ounces per day.  The "cup" markers on your coffee pot are 6 ounces each, so the limit would be about five of those cups.  If you prefer to get your coffee on the go, this would translate into only two "grandes."

This study leaves a lot of questions, such as the association of caffeine on health (the study didn't differentiate between regular and decaf coffee), the actual biological mechanisms of coffee (it has hundreds of phytochemicals besides caffeine), and the confounding factor of smoking with coffee consumption.  In the meantime...  Come on, people, four cups per day should be plenty for anyone.  In fact, beyond the first one or two cups of the day, why not explore the benefits of other healthful beverages such as green tea?

1.  Liu J, Sui X, Lavie CJ, et al. Association of coffee consumption with all-cause and cardiovascular disease mortality.Mayo Clin Proc 2013; DOI:10.1016/j.mayocp.2013.06.020.