Friday, March 15, 2013

Is Fish Healthy? Yes, But Don't Ask Dr. Neal Barnard For An Unbiased Answer


On Friday March 8, 2013, Dr. Neal Barnard, a physician, author and president of PCRM, an organization dedicated to perpetuating veganism among other things, appeared on the Dr. Oz show to promote his new book about preventing Alzheimer's. During the episode, he made a statement that no one should eat fish if they wanted to avoid Alzheimer's. Even Dr. Oz was surprised by Dr. Barnard's complete repudiation of fish in human diets. 

Personally, I was shocked. How could anyone make such a statement, given the preponderance of evidence supporting the health benefits of certain fish, let alone a medical professional?  So I contacted Dr. Barnard to seek further clarification of his controversial position.  He was kind enough to respond and I offer below his full response so that you can reach your own conclusions.

My initial query:

"I am writing for clarification regarding a statement that Dr. Barnard made on the Dr. Oz show this past Friday March 8, 2013. During the show, Dr. Barnard stated emphatically that in order to prevent Alzheimer’s, one should completely avoid fish consumption of any kind. I am hoping you could provide me with any citations of peer-reviewed studies that support his conclusion as my own review of the literature does not support such a statement, particularly in regards to wild Alaskan salmon and other such fish rich in omega-3s and low in saturated fat."

His response:
"Dear Dr. Charlap:

Thank you for being in touch about fish. The question is a good one and one that I’m sure many patients will raise, too. Let me share my perspective. It’s certainly true that, compared with beef fat or chicken fat, fish oils have less saturated fat and more omega-3 fatty acids. In some studies, people who favored vegetable oils and/or fish have had a reduced risk of dementia, compared with people who focused on meatier fare. So that is all to the good. However, as a group, people who eat fish have more weight problems and have a higher risk of diabetes, compared with people who skip animal products altogether. In this regard, let me attach diagrams from two large epidemiologic studies, one in the US and the other in Europe. As you’ll see, the greatest benefit comes from plant-based diets, rather than meat-based or fish-based diets. [Added by me: The studies showed very minimal differences between the vegans and those who ate the unspecified fish.] As you know, excess body weight and diabetes can both increase Alzheimer’s risk. So, for people following a healthful plant-based diet, fish is really a step in the wrong direction. [Added by me: None of the science he produced made this connection. This is just his own hypothesis.  The facts are that studies show, as he even quotes above, that fish consumption decreases cognitive decline, which is obviously the opposite of dementia.]

Here are the numbers: Atlantic salmon is about 40 percent fat, as a percentage of calories. Chinook salmon is around 50 percent. Most of that is not “good” fat. That is, only about 15 to 30 percent of the fat in fish is omega-3, depending on the species. The other 70 to 85 percent is a mixture of saturated and various unsaturated fats. Since every fat gram holds nine calories, fatty fish can easily add to your waistline. You may wish to informally survey your patients about their fish consumption and their weight. You’ll often find that fatty fish set them back.

Of course, fish consumption in general has been controversial for other reasons. Mobile shellfish (eg. lobster, crab, shrimp) are very high in cholesterol—higher than beef, ounce for ounce—and also contribute contaminants, including neurotoxic metals. [My note: For an excellent review of the risks versus benefits of consuming fish with contaminants (see article titled: Fish Intake, Contaminants and Human Health, Evaluating the risks and benefits at http://www.myprorenal.com/images/media/Primarypreventionfishoil.pdf). The conclusion of this paper was, and I quote directly from the study, "Potential risks of fish intake must be considered in the context of potential benefits. Based on strength of evidence and potential magnitudes of effect, the benefits of modest fish consumption (1-2 servings/wk) outweigh the risks among adults..."] I think you could argue that salmon is somewhat better than some other fish species on both fronts, but even so, it does contribute cholesterol and animal fat, along with a varying load of contaminants, none of which is necessary.

So, the bottom line is that a person following a healthy plant-based diet—which has proven so helpful for heart disease and diabetes, and now appears to also apply to Alzheimer’s prevention—would not be expected to derive any additional benefit by adding fish.  Not surprisingly, in the Blue Zones—areas where people live the longest—fish is not a large part of the diet. That applies to Okinawa and Sardinia, just like the other regions. The diet staples come from plant sources. 

Let me make one other observation. You’ll discover that some patients—and even some doctors—become quite emotional about food prescriptions and get bent out of shape if one questions the value of nuts, fish, olive oil, red wine, or some other product. It pays to step back and recognize that we all have the health of our patients in mind. Just as doctors seek second opinions and don’t expect complete concordance in every conclusion, the same is true in nutrition. So it’s good to take a deep breath, keep our lines of communication open, and see where emerging evidence leads us.

I hope this is helpful information. I wish you the very best in your work. 
Neal D. Barnard, MD"

My response:


Hi Dr. Barnard,

Thank you for your prompt response. I have had the pleasure to hear you speak at the American College of Preventive Medicine conference in 2012 and found your talk to be informative. My understanding is that you fully advocate on behalf of a vegan diet and so I can appreciate your position about fish in general. However, I was very concerned to hear you on the Dr. Oz show create a negative link between fish and Alzheimer’s disease. Since you did not differentiate between types of seafood, this was particularly alarming as my knowledge suggests that fish like wild Alaskan salmon may offer specific benefits in preventing or delaying the onset of dementia, including Alzheimer’s. See some of the studies listed at end of this email.

Accordingly, as I am always eager to increase my knowledge and that of my readers/patients, I sought you out for clarification. 

Therefore, please indulge me as I pull out certain quotes from your response for further clarification and comment.

You wrote, “However, as a group, people who eat fish have more weight problems and have a higher risk of diabetes, compared with people who skip animal products altogether.”

In response, I ask if you have any credible studies that support that those who eat wild fish like Alaskan salmon, halibut, lake trout, etc. have more weight problems and a higher risk of diabetes?  I reviewed the two studies you cited and they do not differentiate between types of seafood. As you know, farm raised salmon is a far less nutritional fish than wild salmon as it includes more saturated fat, less omega-3s, less Vitamin D, etc.  Therefore, if you have any specific fish studies that look at particular types of fish in comparison to non-fish eaters, I would appreciate it if you could forward them to me.  I contend that in the absence of such studies, it is a rush to judgment to state that consuming fish leads to Alzheimer’s when studies, as even you cited to me in your response, show an explicit decrease in cognitive loss due to fish consumption.

Furthermore, you wrote, “Here are the numbers: Atlantic salmon is about 40 percent fat, as a percentage of calories. Chinook salmon is around 50 percent. Most of that is not “good” fat. That is, only about 15 to 30 percent of the fat in fish is omega-3, depending on the species. The other 70 to 85 percent is a mixture of saturated and various unsaturated fats.”

As discussed above, it is important to differentiate between wild and farm raised salmon as farm-raised Atlantic salmon has far more than double the saturated fat of wild Atlantic salmon and nearly four times the saturated and total fat of wild Alaskan pink salmon. In addition fat in the pink variety represents far less than the 40% of the total calories of fish that you cite.

You wrote, ”Of course, fish consumption in general has been controversial for other reasons. Mobile shellfish (eg. lobster, crab, shrimp) are very high in cholesterol—higher than beef, ounce for ounce—and also contribute contaminants, including neurotoxic metals. I think you could argue that salmon is somewhat better than some other fish species on both fronts, but even so, it does contribute cholesterol and animal fat, along with a varying load of contaminants, none of which is necessary.”

Let me start with the point you make that “none of it is necessary.”  This is not an accurate statement, as omega-3s are not the only valuable fat in wild salmon. For example, nervonic acid, one of the monounsaturated fats in salmon, plays a valuable role in the biosynthesis of myelin, a key component as you know, of our nervous system.  Again, while certain predatory fish like tuna, and many of the crustaceans tend to absorb the ocean’s pollutants, wild salmon from Alaska and certain lake trout which are non-predatory fish tend to contain few contaminants.  Besides, as you are well aware, many plants are victims of pesticides and other pollutants equal in their potential devastation to human health as anything found in the ocean, and yet you didn’t declare on national television that people equally avoid them like you said about all fish. 

You also wrote, “So, the bottom line is that a person following a healthy plant-based diet—which has proven so helpful for heart disease and diabetes, and now appears to also apply to Alzheimer’s prevention—would not be expected to derive any additional benefit by adding fish.  Not surprisingly, in the Blue Zones—areas where people live the longest—fish is not a large part of the diet. That applies to Okinawa and Sardinia, just like the other regions. The diet staples come from plant sources.”

Again, I am not sure of the source of your information, but in Okinawa fish is a large part of the diet although the diet contains many plant based foods, By the way, not only do the Sardinians eat fish, but they also eat meat and drink goat’s milk all while tracing their men’s extraordinary longevity back to the Bronze Age.

In conclusion, I feel that you do not offer a compelling case due to the lack of scientific support against fish like wild Alaskan salmon as part of one’s diet. If you have further studies that you think would be relevant, I ask that you forward them to me as soon as possible. As a courtesy, I will not publish until Sunday to give you ample time to response.

As for my patients, I advocate eating such fish as wild salmon every other day and have witnessed reversal of hemoglobin A1cs from mid 7s to below 6, cholesterols from 300s to low 100s, and 50+ pound weight loss.  My personal transition to such a diet enabled me to drop 25 pounds to below a 25 BMI and keep it off, while also weaning myself off of statins. Therefore, as you wrote, I agree that “it’s good to see where emerging evidence leads us.” However, I hope you agree that it’s not prudent to suggest to people that emerging evidence supports a conclusion unfounded by the facts, some of which are cited below.
“Emerging evidence” to consider about the benefits of fish:

1.     J Nutr Health Aging. 2011 Aug;15(7):551-4552.
Consumption of fish and Alzheimer's disease.
Newton W, McManus A.
Source
Centre of Excellence Science Seafood and Health, Curtin Health Innovation Research Institute, Curtin University.
http://www.ncbi.nlm.nih.gov/pubmed/21808933

2.     Nihon Rinsho. 2011 May;69(5):953-63.
[Dementia and lifestyle-related diseases in Japanese aging society].
[Article in Japanese]
Iwamoto T.
Source
Toshihiko Iwamoto: Department of Geriatric Medicine, Tokyo Medical University.
http://www.ncbi.nlm.nih.gov/pubmed/21595287

3.     J Nutr Health Aging. 2011 Jan;15(1):25-31.
High dietary and plasma levels of the omega-3 fatty acid docosahexaenoic acid are associated with decreased dementia risk: the Rancho Bernardo study.
Lopez LB, Kritz-Silverstein D, Barrett Connor E.
Source
Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, California 92093, USA.
http://www.ncbi.nlm.nih.gov/pubmed/21267518
4.     Arch Neurol. 2010 Jun;67(6):699-706. doi: 10.1001/archneurol.2010.84. Epub 2010 Apr 12.
Food combination and Alzheimer disease risk: a protective diet.
Gu Y, Nieves JW, Stern Y, Luchsinger JA, Scarmeas N.
Source
The Taub Institute for Research in Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA.
http://www.ncbi.nlm.nih.gov/pubmed/20385883

I can produce many more studies if you are interested.  The bottom line is that certain fish, like those rich in omega-3s and low in other saturated fats, play a critical role in health promotion, including Alzheimer’s prevention, and to suggest otherwise, is to ignore the “emerging facts.”
I mean no disrespect in my response and I trust you will accept it in the spirit intended, which is for all of us to identify the best dietary answers for ourselves, our families, our patients, and the community at large.
I look forward to your response.

To your health,

Steve
  
His response:

"Hi, Steven,

You have the same access that I do to published studies. See what you find. If you can find a study that shows that people who habitually add fish to the diet are as slim and healthy as vegans, I’d love to see it. The epi studies mostly characterize fish-eaters as a group, and they don’t do as well.

All the best,

Neal 

My final response:


"Hi Neal,

Please find seven studies below that clearly show major health benefits associated with fish consumption.

As you know, there are no head to head studies between vegans and vegans who eat fish. While we can agree to disagree on which is better, I ask you to use caution in the future in telling people that all fish is bad for them because I hope you agree, there are clear benefits in consuming certain non-predatory, wild fish rich in omega-3s, antioxidants such as astathanxin (although no conclusive studies), Vitamin D, Vitamin B12, lean protein, etc. Consuming such fish eliminates the need to supplement with Vitamin B12.  I trust you agree that it is always best to get vitamins from nature than from a pill produced in a factory

1. Kromhout D, Bosschieter EB, de Lezenne Coulander
C. The inverse relation between fish consumption and
20-year mortality from coronary heart disease.
N Engl J Med. 1985;312:1205-1209.

2. Burr ML, Fehily AM, Gilbert JF, et al. Effects of
changes in fat, fish, and fibre intakes on death and
myocardial reinfarction: diet and reinfarction trial
(DART).
Lancet. 1989;2:757-761.

3. Daviglus ML, Stamler J, Orencia AJ, et al. Fish con-
sumption and the 30-year risk of fatal myocardial
infarction.
N Engl J Med. 1997;336:1046-1053.

5.Albert CM, Hennekens CH, O’Donnell CJ, et al. Fish
consumption and risk of sudden cardiac death.
JAMA.1998;279:23-28

6. Morris MC, Evans DA, Tangney CC, Bienias JL,
Wilson RS. Fish consumption and cognitive decline with
age in a large community study.
Arch Neurol. 2005;62:1849-1853.

7. He K, Song Y, Daviglus ML, et al. Fish consump-
tion and incidence of stroke: a meta-analysis of co-
hort studies.
Stroke. 2004;35:1538-1542.

In conclusion:

Now you have a well reasoned perspective of pure veganism versus a vegan diet combined with certain fish. Personally, until proven otherwise, I continue to advocate for the inclusion of wild fish like salmon in one's diet on a regular basis (every couple of days) for optimal health. You now have the available facts and both sides of the debate; you be the judge.


4 comments:

  1. Excellent. I never understood vegans aversion to all fish. It usually struck me as political(?)

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  4. Thank you for sharing this! I will continue to take Cod Liver Oil with my plant based vegan diet.

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