Friday, March 25, 2011

Healthy Eating 501: The Paleo Diet

I.   Introduction
II.  Paleo, What??
III.  What Foods are in the Paleo Diet?
IV.  Scientific Support of the Paleo Diet
V. Conclusion
VI.  Bibliography 
I.  Introduction

Recently, I discussed some basic healthy eating recommendations in the article 'Healthy Eating 101' (HE 101).  For some, the recommendations in that post are a huge change and require some time to adjust to that HE 101 lifestyle.  While HE 101 habits are significantly better than the typical, Western, high-fat, high-carbohydrate, low-nutrient diet, there are some drawbacks from the consumption of grains (wheat, rye, barley, oats, etc), legumes (lentils, beans, peanuts, etc), and dairy products.  Some people may be totally unwilling to eliminate these foods from their diets, and I understand that.

Therefore, this post is for those who a) have already passed HE 101 and are seeking "graduate-level" healthy eating curriculum, or b) would like to skip HE 101 and go right to the healthiest type of eating there is.  If you fall into either of those two categories, this post is for you:  

Healthy Eating 501 - The Paleo Diet

II.  Paleo, What??
Some of you may have heard of the ‘Caveman Diet’ and wondered, “What in the world is that”?  Others may have completely blown it off as another fad diet that doesn’t work.  Well hold on, not so fast!  There is serious evidence supporting the value of the Caveman Diet as a safe method for healthy living and weight loss.

The “Caveman”, or Paleolithic, diet refers to a period of time beginning 2 million years ago and continuing until about 10,000 years ago.  During this time, the Homo genus (our ancestors) lived as hunters and gatherers.  They hunted wild animals and used them as sources for lean meats, internal organs, and bone marrow.  They gathered natural foods from plants such as fruits, vegetables, nuts, and other non-grain carbohydrate sources [1, 2].  However, the development of 1) agricultural systems that alter the natural growth of plant-source foods and 2) animal growth and domestication techniques that alter the natural development of animal-source foods, initiated the eradication of the Paleolithic lifestyle [2] by introducing foods that were absent in the Paleolithic diet.  Combined with the industrial revolution, fast-food revolution, and introduction of alcohol, the physiological make-up of the contemporary human being has been dramatically altered [2]. 

A specific example of how modern developments have changed the quality of our food sources is cattle feeding.  Technological developments of the 19th century such as the steam engine and railroads, allowed for larger grain harvests and easier transportation of cattle, which led to the practice of feeding grain to cattle, rather than grass [3].  This change allowed cattle to be rapidly fattened, slaughtered, and sold as meat.  However, the meat taken from overweight, grain-fed cattle has higher saturated fat content and lower healthy fat content [3].  Even though this is known, 99% of beef consumed in the US is from grain-fed, overweight cattle [3].  And the same grain-overfeeding approach is applied to chickens and pigs.

Some of the modern foods that have contributed to the physiological alteration of humans include non-human milk from mammals, meats from grain-fed animals, refined carbohydrates, separated oils, saturated fats, and trans fats [1, 3, 4].  A surprising finding for me was that grains (wheat, rye, barley) have also contributed to this alteration (I will go into great detail into this in Part II, it deserves its own blog).  Multiple generations have made these modern foods a large part of their diets, while neglecting Paleolithic foods, such as lean meats from wild game or grass-fed animals, and natural plant foods (i.e. – organic fruits and vegetables) [2].   Therefore, these modern revolutions have coincided with the increased incidence of modern diseases such as obesity, cardiovascular disease, diabetes, hypertension, osteoporosis, cancer, and sarcopenia (decrease in muscle mass with age) [1, 3, 4].  These diseases are often referred to as the “diseases of civilization”.  And in my opinion, the development and distribution of prescription drugs is the worst solution for those suffering from these disorders.  Rather than changing their eating habits, many people depend on drugs to do magic and heal them.  Well, it should be no surprise that often times, the drugs just make you feel even worse.  It should also be no surprise that many studies support the use of the Paleolithic diet to improve the overall health of individuals suffering from the effects of these modern diseases.  But before going into that, here’s a short list of what can and cannot be eaten in the Paleolithic Diet.
III.  What Foods are in the Paleo Diet?
Foods in the Paleolithic Diet:
1.  Foods that can be hunted or fished: lean meats (free of food additives, wild game meats, grass-fed beef and chicken), fish, and other seafood (purchased raw and unprocessed).
2.  Foods that can be gathered: naturally grown fruits and vegetables, nuts, seeds, eggs from grass-fed chickens, mushrooms, herbs, spices, tubers (sweet potatoes, yams)

Foods not in the Paleolithic Diet:
1.  High glycemic carbohydrates (including potatoes), refined sugars, sweets, artificial sweeteners
2.  Grains (this includes wheat, rye, barley, oats, any type of bread, this was the most surprising to me, but there are reasons why)
3.  Corn
4.  Legumes (lentils, beans, peas, soy, peanuts)
5.  Dairy products
6.  Salt
7.  Processed oils
8.  Anything processed

IV.  Scientific Support of the Paleo Diet
A study by Frassetto et al. (2009) placed non-obese, healthy subjects on Paleolithic diets for 17 days, providing enough calories to maintain their weight.  In their normal diets, caloric intake from protein, carbohydrates (any kind), and fats (any kind) was 18%, 44%, and 38%, respectively.  In their Paleo diets, caloric intake from protein, carbohydrates, and fats (mainly unsaturated) was 30%, 38%, and 32%, respectively.  After the 17-day period, subjects had:

-16% decrease in total cholesterol
-22% decrease in LDL (bad) cholesterol
-No change in HDL (good) cholesterol
-Improved glucose tolerance
-Increased insulin sensitivity
-Decreased blood pressure
-Significant decrease in urine sodium and increase in urine potassium (diets high in sodium and low in potassium play a role in health issues such as hypertension, stroke, kidney stones, gastrointestinal tract cancer). 

A study by Jonsson et al. (2006) was also conducted to investigate the effect of the Paleolithic diet on disease risk factors in domestic pigs.  Piglets were fed either a cereal-based swine feed or Paleolithic foods (fruits, vegetables, meat, and tubers).  After 17 months, pigs on the Paleolithic diet had greater insulin sensitivity, lower blood pressure, and lower C-reactive protein in the blood [5] (High C-reactive protein – greater risk for diabetes, hypertension, and cardiovascular disease).  Even though this study was not in humans, these risk factors can negatively affect the quality of the meat provided from these animals.  We, as consumers, may then ingest byproducts of the damage caused by these increased risk factors in animals. 

A study by Lindeberg et al. (2007) also showed that a Paleolithic diet was more effective in improving glucose tolerance in ischemic heart disease patients than a Mediterranean diet, which consists of “whole grain cereals, low-fat dairy products, potatoes, legumes, vegetables, fruits, fatty fish, and refined fats rich in monounsaturated fatty acids and alpha-linolenic acid.”
V.  Conclusion

So, when you look at the large amount of processed, unhealthy food that is easily accessible, combined with the quality of the meat that we eat, it’s easier to understand why the Paleolithic Diet improves overall health.  But as I alluded to earlier in this post, the exclusion of grains, legumes, and low-fat dairy products was very surprising!  I always thought they were healthy?  I should have been a Quaker spokesperson for all of the oatmeal I ate.  So of course, when I initially saw that grains, legumes, and dairy products were bad, my first reaction was, “That’s pure BS!”  But luckily, I always do my due diligence.  Not only is there good reason why these foods are excluded from this diet, there has been a significant amount of research conducted on some of the toxic effects of grains, legumes, and dairy products.  Don’t get me wrong, they do have positive properties, but they also have negative ones that can affect your well being.  Gathering this knowledge has truly made me re-assess what I eat and what is truly healthy.  I’ll go into greater detail on these toxic effects in Part II…so DON’T MISS OUT!!!

Dr. O 
"I don't live to eat...I eat to live!"

For Paleo-Friendly Snacks, check out!
VI. Bibiliography
1.            Eaton, S.B., M. Konner, and M. Shostak, Stone agers in the fast lane; chronic degenerative diseases in evolutionary perspective. Am J Med, 1988. 84: p. 739-749.
2.            Frassetto, L.A., et al., Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet. Eur J Clin Nutr, 2009. 63: p. 947-955.
3.            Cordain, L., et al., Origins and evolution of the Western diet: health implications for the 21st century. Am J Clin Nutr, 2005. 81: p. 341-354.
4.            Lindeberg, S., et al., A Paleolithic diet improves glucose tolerance more than a Mediteranean-like diet in individuals with ischemic heart disease. Diabetoligia, 2007. 50: p. 1795-1807.
5.            Jonsson, T., et al., A Paleolithic diet confers higher insulin sensitivity, lower C-reactive protein, and lower blood pressure than a cereal-based diet in domestic pigs. Nutr & Metab, 2006. 3(39).

Sunday, March 13, 2011

Benefits of Exercising During Pregnancy

I.  Introduction
II.  Gestational Diabetes Mellitus
III. Pre-eclampsia
IV. Pre-term Delivery, Birth Weight, and other Benefits
V.  Author's recommendations
VI. Bibliography
 I.  Introduction

If you didn’t know by now, unhealthy eating habits put us at risk for developing many disorders such as cardiovascular disease and cancer.  However, pregnant women who live unhealthy lifestyles also put their unborn child at a much greater risk for health complications.  Aside from abundant health issues associated with unhealthy eating, women with a high pre-pregnancy BMI or women who consume large amounts of saturated fat and simple carbohydrates are at risk for developing gestational diabetes mellitus or pre-eclampsia.  Newborns are also at a greater risk for abnormal birth weight, pre-term delivery, obesity or type 2 diabetes later in life.

As some may assume, proper dieting and exercise is often prescribed to at risk pregnant women to prevent the development of these ailments.  I won’t focus on the dieting, because I don’t think that the benefits of healthy eating during pregnancy can be disputed.  Many health ailments can be avoided by following the eating habits that I outlined in ‘Healthy Eating 101’.  However, some women may not want to exercise during pregnancy in fear of its effect on their unborn child.  Well, the fact is, a sedentary life is more likely to negatively effect your child’s development than an active life.  Hopefully this column will change some of those minds.

Many researchers have investigated the benefits of recreational exercise or leisure time physical activity (LTPA) during pregnancy.  Common types of this exercise include brisk walking, bicycling, canoeing/rowing for pleasure, dancing, exercising on a treadmill or elliptical, gardening, playing golf, playing tennis, aerobics, jogging, or swimming (just to name a few).  Some of the studies that will be discussed do not specify one type of recreational exercise, so keep this list in mind.  

II.  Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a form of hyperglycemia in which insulin supply is not adequate to meet the body’s demands for blood glucose regulation.  In a normal pregnancy, the ability of insulin to clear glucose from the blood progressively decreases beginning near mid-pregnancy, developing an insulin resistance similar to that of type 2 diabetes.  To counteract this, pancreatic β cells increase their insulin secretion to compensate for this insulin resistance in pregnancy [1].  However, most women who develop GDM have already developed a chronic insulin resistance [1], which can develop from a diet high in carbohydrates that are high on the glycemic index [2] and results in decreased pancreatic β cell function [1].  This disorder puts women at high risk for developing diabetes following pregnancy [1].  It may also lead to pre-term delivery, which dramatically increases infant mortality.   As you might expect, insulin sensitivity can be increased with low GI, high-fiber diets with more protein and vegetable consumption [3, 4], thus lowering the risk of GDM.  However, exercise is also an effective way to lower GDM risk.

Various studies by Dempsey et al. have demonstrated the ability of exercise before and during pregnancy to reduce the risk of obtaining GDM.  Results from these studies show that women who participated in recreational exercise during the first 20 weeks of pregnancy had a 48% reduction in risk of GDM when compared to inactive women [5].  Women who took part in recreational exercise for ≥ 4.2 hours per week the year before pregnancy also demonstrated a 76% decrease in GDM risk [6].  Lastly, women who exercised both before and during pregnancy experienced a 69% GDM risk reduction [6].
III.  Pre-eclampsia

Pre-eclampsia is a dangerous pregnancy complication that affects as many as 10% of pregnancies per year.  Symptoms include high blood pressure and excessive protein in urine that may develop from 20 weeks gestation.  While the exact mechanism is unknown, some theories suggest that diet, endothelial dysfunction, insulin resistance, coagulation activation, and increased inflammatory response may play a role [7]. Pre-eclampsia also increases the risk of pre-term delivery.

As is the case with GDM, physical activity can also reduce the risk of developing pre-eclampsia. 

A study by Sorensen et al. has shown that [8]:
1.  Women who participated in recreational exercise during early pregnancy had a 35% reduction in risk of pre-eclampsia when compared to inactive women.
2.  Women who participated in recreational exercise one year prior to pregnancy had a similar reduction in pre-eclampsia risk.
3.  More specifically, women who exercised for 3.8-6.7 hours per week during the first 20 weeks of pregnancy had a 68% reduction in risk of pre-eclampsia.
IV.  Pre-term Delivery, Birth Weight, and other Benefits

One important predictors of the survival and health of a newborn is the time of delivery.  A normal pregnancy typically should last about 40 weeks.  Pre-term delivery occurs when a pregnancy ends between 20 and 37 weeks.  When this occurs, the newborn is much more at risk to many health problems, neonatal mortality, and neonatal morbidity [7].  Birth weight is also a great predictor of newborn health.  Infants with birth weights of < 2,500 g have increased risk of mortality, morbidity, adulthood hypertension, and diabetes [7].  Infants born at birth weights of > 4,000 g have also been shown to increase the risk of adulthood type 2 diabetes and breast cancer (in females) [7]. 

Fortunately, recreational exercise can reduce the risk of both pre-term delivery and unhealthy birth weights.  Pregnant women who participated in recreational exercise demonstrated a 50% reduction in risk for pre-term delivery [9].  Studies also showed that aerobics, jogging, swimming, moderate-fast biking) during the first or second trimester does not increase the risk of pre-term delivery [10].  Also, the reduction in GDM risk from exercise suggests that exercise reduces GDM-induced pre-term deliveries.

Recreational exercise also reduces the risk of unhealthy birth weights.  A study conducted by Clapp et al. placed sedentary, pregnant women on an exercise program for 20 min, 3-5 times per week, beginning at 8 weeks and continuing through the duration of the pregnancy.  The exercise program consisted of treadmill exercise, step aerobics, or a star stepper at a low intensity (55-60% pre-conception VO2 max).  Women in the exercise group gave birth to babies with significantly more lean body mass, length, and weight.  Placental growth rate and function were also greater in the exercise group [11]. 

Other benefits of exercise during pregnancy [12]:
-Maintenance of vascular reactivity and blood volume, which can decrease in sedentary pregnant women, leading to hypotension (low blood pressure) or arrhythmias (irregular heart rate).  Women who exercise prior to pregnancy and maintain it during pregnancy are protected the most.
-Vascular remodeling within the uterus is heightened; increases placental size and uteral blood flow.
-Glucose utilization is increased while lowering insulin secretion (lowers risk of GDM)
-Women gain less weight, maintain posture, and maintain abdominal muscle tone following child birth.
-Babies have decreased fetal distress before or during labor, decreased growth of fat, and normal to superior cognitive development.
V.  Author's Recommendations

1.  If you are currently sedentary but plan to conceive a child within the near future, begin a regular exercise routine to lower the risk of GDM, pre-eclampsia, and improve the development of your child.
2.  During pregnancy, continue to exercise 3 or more times per week for 30-60 min (see the list of exercise routines in the introduction)
3.  Keep your doctor informed about your exercise regimen in order to monitor your health and the healthy development of your child.

The key to ending many diseases that kill us is to stop facilitating the reproduction of children genetically pre-disposed to developing these diseases.  And it starts with the parents…even before conception...

Dr. O 
"I don't live to eat...I eat to live!"
VI.  Bibliography

1.       Buchanan, T.A. and A.H. Xiang, Gestational diabetes mellitus. Clinical Investigation, 2005. 115(3): p. 485-491.
2.       McKeown, N.M., et al., Carbohydrate Nutrition, Insulin Resistance, and the Prevalence of the Metabolic Syndrome in the Framingham Offspring Cohort. Diabetes Care, 2004. 27(2): p. 538-546.
3.       Boden, G., et al., Effect of a Low-Carboydrate Diet on Appetite, Blood Glucose Levels, and Insulin Resistance in Obese Patients with Type 2 Diabetes. Ann Intern Med, 2005. 142(6).
4.       Fukagawa, N.K., et al., High-carbohydrate, high-fiber diets increase peripheral insulin sensitivity in healthy young and old adults. Am J Clin Nutr, 1990. 52: p. 524-528.
5.       Dempsey, J.C., et al., A case-control study of maternal recreational physical activity and risk of gestational diabetes mellitus. Diabetes Res Clin Prac, 2004. 66(2): p. 203-215.
6.       Dempsey, J.C., et al., Prospective Study of Gestational Diabetes Mellitus Risk in Relation to Maternal Recreational Physical Activity before and during Pregnancy. Amer J Epidem, 2004. 159(7): p. 663-670.
7.       Hegaard, H.K., et al., Leisure time physical activity during pregnancy and impact on gestational diabetes mellitus, pre-eclampsia, preterm delivery and birth weight: a review. Acta Obste Gyn, 2007. 86: p. 1290-1296.
8.       Sorensen, T.K., et al., Recreational Physical Activity During Pregnancy and Risk of Preeclampsia. Hypertension, 2003. 41: p. 1273-1280.
9.       Berkowitz, G.S., et al., Physical activity and the risk of spontaneous preterm delivery. Reprod Med, 1983. 28: p. 581-588.
10.     Evenson, K.R., et al., Vigorous leisure activity and pregnancy outcome. Epidemiology, 2002. 13: p. 653-659.
11.     Clapp, J.F., et al., Beginning regular exercise in early pregnancy: Effect on fetoplacental growth. Amer J Obstet Gyn, 2000. 183(6): p. 1484-1488.
12.     Clapp, J.F., Exercise during Pregnancy: Risk and Benefits, in Protocols for High-Risk Pregnancies: An Evidence-Based Approach, ed. J.T. Queenan, J.C. Hobbins, and C.Y. Spong. 2010, Oxford, UK: Wiley-Blackwell.