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Friday, April 18, 2014

Vegan, or Not Vegan? My Question About the Latest Vegan Research Report

Comparison of Nutritional Quality of the Vegan, Vegetarian, Semi-Vegetarian, Pesco-Vegetarian and Omnivorous Diet



This new study reports that Belgian people eating strictly plant-based diets have lower body mass and better overall food choices and nutrient intakes than people eating vegetarian, semi-vegetarian, pesco-vegetarian, or omnivorous diets. Those eating 'vegan' diets had diets receiving the highest scores when measured by both the USDA Healthy Eating Index and the Mediterranean Diet Index. That means that those eating plant-only diets had diets more like the Mediterranean Diet 'guidelines' than those eating any other diet category. "Vegans" consumed more than adequate protein (82 g/d on average), iron, B12, and had apparently adequate calcium intake (although calcium intake was lower than other groups).

But I found something odd in this paper that leads me to put "vegan" in scare quotes.

The researchers defined "vegan" as "not consuming any animal products" and also stated "Subjects describing themselves as vegans in the diet questionnaire, though declaring to consume animal products in the FFQ as well as reported vegetarians declaring to consume meat as indicated by the FFQ were reclassified according to their answers given in the FFQ."  This should have meant that they only included people who declared no animal product consumption, and therefore virtually no cholesterol intake, in the vegan group.


Strangely, Table 2, titled "Nutritional intake across the dietary patterns," reports that the "vegans'" consumed 149 mg cholesterol daily with a standard deviation of 92.  This appears to imply that none of the 'vegans' in this study ate a vegan diet as defined by the researchers.


Cholesterol in Plants?

Yes, plants do manufacture and utilize very small amounts of cholesterol.  According to some biochemists plants contain roughly 50 mg cholesterol per kg total lipids, i.e. 0.05 mg/g total lipids.


http://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/Cholesterol.svg/500px-Cholesterol.svg.png
Cholesterol.  From Wikimedia.


In comparison, animal tissues have 5 g cholesterol per kg total lipids, or more, i.e. one hundred times more than plants.  Consequently, the amount of cholesterol in plant foods is negligible.  The richest plant sources of cholesterol are extracted plant oils.  According to Behrman and Gopalan, cottonseed, canola, and corn oils supply, respectively, 45, 53, and 55 mg cholesterol/kg total lipids.  Of interest, highly saturated coconut supplies only 14 mg/kg total lipids.  Olive oil supplies 0.5-2 and sesame oil ~1.0 mg/kg total lipids.  Of course in many whole plant foods, the absolute amount of lipids is very low resulting in very very low amounts of total cholesterol.

This study reports that the "vegans" consumed an average of 68 g total fat daily (compared to 122 g total fat among omnivores).  According to the data on plant cholesterol, that would entail a plant cholesterol intake of up to ~ 3.5 mg daily. Thus, I wonder how the researchers calculated that these "vegans" consumed an average of 149 mg cholesterol daily, roughly 40-50 times what would be expected from a strictly plant-based diet providing only 68 g total fat daily. Those with the

How much animal food would one need to consume to ingest ~ 149 mg cholesterol daily?  This is more than the amount supplied by a small whole egg (141 mg) or equal to the amount found in 240 g (roughly 8.4 ounces) of grass-fed bovine muscle meat (62 mg/100 g). 

The authors claim that they excluded from the "vegan" group anyone who reported consuming any animal products, yet also reports that the "vegan" consumed significant amounts of cholesterol potentially representing rather large amounts of animal flesh.  Their data contradicts their claimed methodology.

I can think of several possible problems.  Possibly they did not as claimed exclude from the "vegan" group people who claimed consuming animal products, therefore their "vegan" group was not actually composed of vegans.  Another possibility is this is a clerical error, but it surprises me that no one on this team of researchers nor the peer-reviewers noticed this glaring inconsistency.  It very much warrants some explanation which the authors did not provide. 

These "vegan" dieters had a lower average cholesterol intake than the other groups, but it was not low enough to convince me that they researchers only included vegans in their "vegan" group. This issue leaves me lacking full confidence in their data collection and/or tabulation.


More Data From the Study

In this study, the "vegans" consumed about 21 g saturated fat daily, omnivores, 54 g.  The vegetarian, semi-vegetarians, pesco-vegetarians, and omnivore intakes of saturated fats were 13, 14, 14, and 16 percent respectively.  Only "vegans" had a saturated fat intake less than 10 percent of calories
(8 percent), but I wonder if this data is compatible with a cholesterol intake of 149 mg/d.


Sodium intakes were also lowest among the "vegans," intermediate in the semi-vegetarian groups, and highest among the omnivores.  Plants contain far less sodium than animal tissues so this is consistent with expectations.

The "vegans" had the highest carbohydrate intake as a percent of energy (57%), and the omnivores the lowest (44%).  That is expected because plants are composed largely of carbohydrate and animal products contain little or none.  "Vegans" also had the highest intake of empty calories (solid fats, alcohol, and added sugars), 8.5% vs. 5.7% for the omnivores.

According to self-reported data, the "vegans" also had the lowest incidence of overweight (11%) and obesity (2%) while the omnivores had the highest (21% and 8%, respectively).  This data is consistent with the fact that the "vegans" had the lowest average total energy intake, and also with previous reports, such as EPIC-Oxford, which I discussed at length in Powered By Plants.

"Vegans" consumed about 23 mg iron daily, omnivores, 17 g.  This accords with other studies and also my own experience planning plant-based diets.

The "vegans" also had the lowest calcium intake, 738 mg per day, which according to recent research is about what the typical individual requires to maintain calcium balance.   However, my diet typically provides more than 2000 mg of calcium daily from plant foods, because I eat a very large amount of green leafy vegetables, fruits, nuts, and seeds rich in calcium, and also use tofu or fortified soymilk almost daily.  I think "vegans" can do better than 738 mg calcium per day with a little effort.

Summary

Although most of the reported data from this study fits expectations and accords with previous data comparing vegans, vegetarians, semi-vegetarians, pesco-vegetarians, and omnivores, I lack full confidence in the reported nutrient intakes of the "vegans" in this study because of the odd report of a substantial cholesterol intake in the "vegans."  I would like the authors to explain this portion of their data because it does not accord with the expected cholesterol content of an exclusively plant-based diet.  








Thursday, April 10, 2014

Review of Bomba Gear Gymnastics Rings from Fringe Sports

I recently purchased a pair of Bomba Gear Handmade Wooden Gymnastics Rings from Fringe Sports.  Tracy and I have used them for a few weeks now.  Here is a clip of some of the progress Tracy made on the rings in just one week following the training routine I designed.


We like the Bomba Gear Rings a lot.  The handmade wooden rings are not slippery when my hands are perspiring, so I haven't needed chalk so far.  The heavy duty straps are more than 18 feet in length, marked in 1/4 foot increments with embroidery, and have a heavy duty motorcycle cam-buckle that makes it easy to quickly adjust both rings to the same height.  The rings are rated for 1000 pounds and the straps for 3800.  At only $65 I think they are a great value, so I decided to put up a video review. 

Wednesday, April 9, 2014

Our Close Encounter With A Friendly Wild Duck

Tracy and I went to Chaparral Park in Scottsdale on Sunday and after we had walked around the 'lake' we sat down to talk.  A female mallard surprised, delighted, and honored us with her presence while we sat, and eventually allowed Tracy to pet her for a few moments.  We both felt deeply moved by the encounter.  Here's a brief video of the wonderful event.

And here's a longer video of some of the other beautiful, fun and interesting things we enjoyed in our visit to Chaparral Park.  Perhaps you have time to enjoy some of it vicariously.

Wednesday, March 19, 2014

The Wahls Protocol – Paleo Magic or Faulty Logic?

Terry Wahls, author of The Wahls Protocol, asks "Could Vegetarianism Increase Your Risk Of Autoimmune Disease?"
 
In this article Wahls suggests that she developed multiple sclerosis because she adopted a 'vegetarian' diet in her teen years after reading Frances Moore Lappe's Diet for a Small Planet. 

Wahls writes:

"I eventually chose medical school instead of vet school. As a student, I lived on beans and rice, whole-grain bread, eggs and cheese, vegetables and fruit. At the time, the medical profession promoted a low-fat, low-cholesterol diet. I disagreed with this on an intuitive level. I ate eggs and cheese in addition to my beans and rice, believing I needed the fat and protein for my high-energy lifestyle. Through med school, my internship, and various relationships, I remained a vegetarian."

This tells us that her 'vegetarian' diet included plenty of animal protein, saturated fats, and cholesterol, and that she mistakenly believed that fat and protein are the best sources of energy for a physically and mentally active young adult.  Cheese and eggs are the richest dietary sources of saturated fats and cholesterol, respectively.  Dairy fat has the highest proportion of saturated fats (~54%) and 100 g whole egg supplies 372 mg cholesterol, whereas 100 g of grass-fed beef supplies only 62 mg, i.e. the eggs have on a weight basis 6 times the cholesterol of the beef.  One egg also provides ~5 g saturated fat.

Saturated fat consumption increases the risk of developing multiple sclerosis, and MS patients have higher nerve membrane levels of shorter-chain SFAs than controls. 1, 2  

The 2013 Atlas of MS, page 8, shows that MS primarily afflicts people in affluent nations eating animal-rich diets.  Nations that consume large amounts of dairy products – U.S.A., Canada, Scandinavian nations – have the highest prevalence.  The regions with high intakes of grains and legumes but lower intakes of land animal flesh, dairy products and eggs – Africa and Asia – have a low prevalence.  Anyone claiming that grains and legumes cause MS needs to explain why the nations with the highest intakes of grains and legumes have the lowest prevalence of the disease.




Based on this ecological data indicating that the prevalence of MS is many times greater in regions consuming diets high rather than low in saturated fat, in the 1950s Roy Swank developed a low-fat diet protocol for MS.  Over the course of 34 years of treatment, Swank reported:

"Minimally disabled patients who followed diet recommendations deteriorated little if at all, and only 5% failed to survive the 34 yr of the study, whereas 80% who failed to follow diet recommendations did not survive the study period."3
Of important interest, the Swank diet allows unlimited intake of whole grains and legumes, including wheat and soy. 4 Swank proposed an explanation for the role of saturated fats in MS:
“During digestion all fats are first reduced to small globules of fat and then to chylomicra in the blood. These chylomicra collect in the small arteries from which feeding capillaries arise. After a large fatty meal, the chylomicra are crowed together and form aggregates.  When formed from unsaturated fats (oils), aggregates are relatively small and loosely held together.  The aggregates are small enough to enter and pass through the capillaries and nourish the tissue.  Conversely, saturated fat aggregates are much larger and tightly bound together. They may or may not enter the capillaries and, due to their size, may get lodged in the capillaries or very slowly pass through.  The rigidity of the aggregates makes them less easy to deform by the shear forces than the softer aggregates formed from the lower molecular weigh droplets from vegetable oils.  As a result the tissues to be nourished by the large aggregates fail to receive adequate nourishment and may starve or function poorly.
"Multiple scattered lesion or malfunction will result in all tissues and organs of the body due to the temporary blockage of the feeding capillaries and subsequent poor nourishment.  We suggest this is a cause of MS when these lesions occur in the central nervous system.  The damage due to the obstruction of feeding capillaries and starvation of scattered tissue may be a contributing factor in aging and the deterioration of other organs resulting in disease such as diabetes and heart disease. All the surviving patient in the [Swank low-fat diet MS] study on low saturated fat show youthful facial condition, demonstrating the efficient microcirculation in the subcutaneous tissue.” 5
Dairy and eggs are also among the eight foods that account for 90 percent of food allergy reactions in the United States. 6  Cow milk and chicken egg proteins are among the most allergenic proteins consumed by humans. 

MS risk is increased by diets rich in animal products, and reduced by plant-based diets.   7  Cow milk consumption has a strong worldwide correlation with MS incidence.  8, 9

In contrast, some research suggests that some peptides present in at least one cereal grain (rice) may be in part responsible for the low prevalence of MS in Asian rice-eating populations. 10

 Wahls reports adopting a dairy- and egg-free diet to treat her MS. 

"I began experimenting on myself, and one of my first discoveries was the work of Dr. Ashton Embry, who had connected diet to multiple sclerosis. Nobody had ever suggested to me that there could be any connection between multiple sclerosis and diet (the mainstream medical literature continues to deny the connection).

"Dr. Embry’s son had multiple sclerosis, and he wrote that a diet without grains or dairy products that included meat could have a dramatic effect on MS progression. I decided it was worth a try. At first, the thought of eating meat was nauseating to me, both physically and morally. I wanted desperately to heal, and I was willing to try just about anything, but by this time I had been a vegetarian over 15 years."


She also writes "I would refine it further, not only eliminating foods that were causing problems for me (grains, legumes, dairy, and eggs)..." 

From this experience, Wahls concludes that avoiding meat caused her to get MS, and that eating meat cured her and is essential to human nutrition:


"I once was a vegetarian because of my conscience, but now, as a doctor, I can no longer in good conscience recommend it.

She seems oblivious to the significance of removing dairy and eggs, the richest dietary sources of cholesterol and saturated fats, from her diet.  As quoted above, she says that she disagreed with the recommendations for a low-fat, low-cholesterol diet "on an intuitive level."  Yet removing these high-fat, high-cholesterol foods from her diet improved her condition.  How good was her intution?  And should a medical doctor rely on "intuition" when there is data to be had? 

Sorry to say, I am surprised and dismayed that someone with such weak reasoning skills can have graduated from medical school.   This woman grew up on a farm, "milking the cows" daily, eating eggs, dairy products, and the flesh of chickens, cows, and pigs, until her teen years, then persisted for 15 years eating "eggs and cheese" for fat, protein, and "energy" as a part of her "vegetarian" diet and she thinks that eating grains and beans caused her MS and eating meat cured it?  Does she recognize that eggs and cheese are not plant foods?  Does she not realize that her diet was rich in saturated fats, cholesterol, and animal products all along?  Does she rely on her "intuition" to determine the cause of MS, even when it conflicts with the data?  Does she even care about the data?

She writes:

"I eventually developed the Wahls Diet, which focuses on vegetables and fruits: 9 cups every day, divided into 3 cups of leafy greens, 3 cups of brightly colored fruits and vegetables, and 3 cups of sulfur-rich vegetables, as well as a regimen of organ meats and sea vegetables"

The patients in the Swank study achieve the same results or better than hers.  Based on the data we have about MS, and the proven success of the Swank protocol for MS (low saturated fat plant-based diet) her improvement was caused by avoiding dairy and eggs, not by adding meat or avoiding grains and legumes. The common factors are reduction of dairy and egg products, and increase of vegetables and fruits, not consumption of organ meats, which are not emphasized on the Swank diet, but are relatively low in fat.  For example, beef liver supplies only 1.5 g fat and 0.5 g saturated fat per ounce, compared to cheddar cheese's 9.4 g total fat and 6 g saturated fat per ounce; the cheese has 6 times as much total fat and 12 times as much saturated fat.  By removing cheese and eggs from her diet and substituting beef liver or other organ meats, she sustains a very significant reduction in total and saturated fat intake. There is no paleo diet magic here.  Her protocol is lower in fat and saturated fat than the diet that she ate for years before her MS diagnosis, including her "vegetarian" diet.  Further, vegetables and fruits supply many anti-inflammatory compounds including dietary salicylic acid, which improves blood circulation. 

Finally, to answer her posed question: Yes, a "vegetarian" diet could very well increase your risk of autoimmune disease, because a "vegetarian" diet can include plenty of animal protein, fat, and saturated fat from dairy products and eggs.  But a whole foods plant-based diet does not include dairy, eggs, or any other animal matter as staple foods.  Dr. Wahls came to some right conclusions – avoid dairy and eggs, eat more vegetables – and some wrong conclusions – eat more organ meats – by some faulty logic.  She believes in a false dilemma, that we must choose between eating ethically, or suffering MS or other autoimmune diseases.  The evidence I have cited indicates that she could have both her ethics and her health by choosing a whole foods plant-based diet.