Dr. David Jenkins Finds Monounsaturated Fats - Like Olive and Canola Oils or Nuts - Raise HDLs and Boost Heart Health. There's More to the Story

 

Eat Nuts, Canola and Olive Oil to Boost Heart Health.  Not So Fast!

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If you just heard about Dr. David Jenkins' hot-off-the-press study about how a low-cholesterol diet can be improved by adding monounsaturated fats (MUFA), which are commonly found in nuts, seeds, avocados, and oils such as olive oil, canola oil and sunflower oil, you may want to hear the full story.

According to the press release, patients with mild to moderate elevated cholesterol levels, who followed the cholesterol-lowering Portfolio Diet, that included the addition of monounsaturated fats, increased their HDLs by 12.5% and lowered their LDLs by 35%.   As always--there's more to the story than meets the eye.

Number 1 point left out:  Both study groups who followed the Portfolio Diet (a vegetarian diet high in beans, legumes, fruits, vegetables, and whole grains) experienced a whopping 35% decrease in their LDL levels--whether they were in the low or high monounsaturated fat (MUFA) group.  Click here for the full article.  Click here for the lay-language press release.

In a nutshell:

Researchers randomly assigned 17 men and seven postmenopausal women with mild to moderate elevated cholesterol levels to either a high-MUFA diet or a low-MUFA diet.

Both groups consumed a vegetarian diet that included oats, barley, psyllium, eggplant, okra, soy, almonds and a plant sterol-enriched margarine. In the high-MUFA group, the researchers substituted 13 percent of calories from carbohydrates with a high-MUFA sunflower oil, with the option of a partial exchange with avocado oil.

In the high-MUFA group, levels of "good" cholesterol (high-density lipoprotein cholesterol, or HDL) increased 12.5 percent while levels of "bad" cholesterol (low-density lipoprotein cholesterol or LDL) decreased 35 percent, according to the report in the Nov. 1 issue of CMAJ, the Canadian Medical Association Journal.

What the press release left out from the article:

"There were no treatment differences in terms of changes in triglycerides, LDL cholesterol or apolipoprotein B [between the two groups].

The prescriptive nature of the diet was another limitation, since adherence to a diet may be considerably less for a self-selected diet consumed under real-world conditions.  The long-term effect on self-selected diets remains to be determined, in terms of compliance and in terms of the lipid response and, ultimately, cardiovascular outcomes.

Exercise and moderate alcohol consumptions may be regarded as pleasurable ways of raising HDL cholesterol.  Weight loss and smoking cessation, although effective in raising HDL cholesterol, are more challenging for many people."

-Dr. David Jenkins, St. Michael's Hospital, Toronto, Ontario, lead author of "Adding monounsaturated fatty acids to a dietary portfolio of cholesterol-lowering food in hypercholesterolemia."  CMAJ. 2010 Nov 1. [Epub ahead of print]-  click here to read the full article.

 

There it is!  Exactly what we've all longed to hear.  Now we can safely enjoy nuts, olive oil, and avocados and get healthy at the same time.  Raise our HDLs, increase our apolipoprotein A1 (the component of HDL that helps clear cholesterol from the blood), and lower our C-reactive protein scores (measure of inflammation).

But, hold on, before you load up on nuts and olive oil, consider this.

• Jenkins' dieters had all their meals provided for them for 2 months--measured out precisely.  No estimates here.
• 13% of the carbohydrate calories were taken away from the high-monounsaturated group to make room for the sunflower oil.  And they weren't given nuts or olive oil--it was sunflower oil!  Not exactly the same as just adding 2 tablespoons of olive oil and 2 ounces of nuts to your diet.  Both high and low monounsaturated fat groups in the study were eating about 2400 calories a day--so that meant they substituted 336 calories of the carbs for about 2 tablespoons of oil a day--almost a meal's worth of calories.  Click here to see exactly what the dieters were eating.
• There was no change in weight loss between the two groups (high & low monounsaturated fats) 
• There was no change in triglycerides between the two groups.  And consider this about triglycerides:

"When triglycerides go up over 100 we start making abnormal forms of cholesterol--the small dense LDLs that are atherogenic and penetrate much more rapidly into the arteries than normal large LDLs. 

When triglycerides start going up--and the changes start around 80-100--nearly everyone with triglycerides over 100 is making significant amounts of small dense atherogenic LDL--above 150 almost all LDL particles are small dense and atherogenic."

-Dr. Patrick E. McBride, Professor of Medicine and Family Medicine, University of Wisconsin, and a member of the Expert III NCEP Panel setting cholesterol guidelines-

To read more about the importance of keeping triglycerides low here.

• The large decreases seen in the C-reactive protein test is something very important to pay attention to--and certainly intrigues me--and it wasn't discussed much in the article or press release.  Inflammation is one of the key drivers of heart disease.
• Olive oil may be considered a monounsaturated fat, but it's also high in omega-9, an oleic acid--and maybe not something beneficial to heart health.

"Contrary to our hypothesis, our study found that omega-9 (oleic acid)--rich in olive oil, impairs endothelial function after eating.  If you've been using olive oil because you think it's healthy, it's time to think again. "  Read more about the less healthy attributes of olive oil here.

"The beneficial components (of the Mediterranean Diet) appear to be anti-oxidant rich foods, including vegetables, fruits, and their derivatives. Dietary fruits, vegetables and their products appear to provide some protection against the direct impairment of endothelial functions produced by high-fat foods, including olive oil." (Vogel study: a meal containing olive oil impairs blood flow & vasodilation by 31%--and that was in healthy men)

 -Dr. Robert Vogel-

• From Dr. Lawrence Rudel of Wake Forest University Baptist Medical Center:  Rudel ran a five year study feeding  olive oil and saturated fat to African Green monkeys.  The monkeys metabolize fat in the same way as humans, so they're good stand-ins.. At the end of five years, their autopsies showed that the monkeys who were fed olive oil had higher HDLs (the good cholesterol) and lower LDLs (the bad cholesterol) than the ones fed the saturated fat diet.  The big surprise here:  Both groups had exactly the same amount of coronary artery disease.  The higher HDLs & lower LDLs of the olive oil group were meaningless.  Rudel later repeated the study on rodents, and got the same results.
• According to Dr. Caldwell Esselstyn, low HDLs in the presence of very low LDLs is of little concern--and commonly seen in many of his patients who have eliminated nuts & oils--as well as  successfully prevented or reversed heart disease.  When your LDLs are low (common when oils & animal products are eliminated) you just don't need high HDLs to remove them from the blood.  Many of the Tarahumara Indians, who exhibited no heart disease, had low LDLs & low HDLs. 
• Take a long hard look at the saturated fat content, and the high omega 6 content of most of the nuts--except for the humble English walnuts--which have a nice 4:1 omega-6 to omega-3 ratio.

When considering nuts, look to the English walnut--and be sure to swap out carb calories for the nuts eaten.  7 walnuts = 1 ounce = 185 calories.  For me, since I eat about 1500 a day, that would mean eating about 7 walnuts, which would also mean eliminating a bowl of oatmeal or a whole grain hamburger bun. 

I have to admit, when I cut out nuts & olive oil my HDLs did drop.  But, I'm still sticking to the elimination of added oils--because I love the subsequest weight loss, and the loss of my belly fat--yet I still feel quite comfortable about eating a few walnuts, or a homemade cocoa-walnut-chia bar--especially after burning 400 calories with exercise.  Click here for the recipe.

What's Could Be Wrong with Nuts?  from Jeff Novick, MS, RD, a dietitian who works with  Dr. John McDougall.  Cick here for full link

"The other issue is Omega 6s (and saturated fat) and making sure we do not get in too much of either. Ideally, saturated fat should be under 5% of our calories and the omega 6 to 3 ratio should be under 4:1 with under 2:1 even better.

Unfortunately, some nuts are very high in omega 6s and some are higher in saturated fat. So if you include any of these you would not want to over do them.

Most nuts have little if any omega 3s so they have very very poor ratios of omega 6 to omega 3s.

Black Walnuts are 16:1
English Walnuts 4:1
Pecans are 20:1
Pistachio is 37:1
Pine Nuts are 300:1
Macadamia is 6:1
Hazelnut is 88:1
Cashew is 117:1
Brazil Nut is 1000:1
Almonds 1800:1
Pumpkin Seeds 117:1
Sunflower Seeds 300:1

CA Avocados 15:1
FL Avocados 16.5:1

Flaxseed 3.9:1 ***
Chia Seed 3:1 ***

(***these is a reverse ratio as the omega 3 is higher than the omega 6)

In regard to Saturated fat

Black Walnuts are 5%
English Walnuts are 8%
Pecans are 8%
Pistachio is 8.5%
Pine Nuts are 6.6%
Macadamia is 15%
Hazelnut is 6.5%
Cashew is 12.5%
Brazil Nut is 21%
Almonds are 6%
Pumpkin Seeds 14%
Sunflower Seeds 6.5%

Flaxseed 6%
Chia Seed 6%

CA Avocados 11.5%
FL Avocados 15%

As you can see, most are not bad, but some are fairly high in saturated fat and some are really high in omega 6s. Some of these, like cashews may not be great choices. They are over 12% saturated fat and have a ratio of 117:1 Pumpkin seeds and brazil nuts are also not the best choices as they are also "higher" in saturated fat and have a "higher" ratio.

It looks like English Walnuts would be the best choice by far.

As always, go to the original research article--get the full story--and consider what impact other studies may have on the conclusions.  For me, I'm comfortable with keeping out the added oils, eating walnuts, and an occasional slice of avocado.  And I'm happy to increase my HDLs with exercise, and an occasional glass of Pinot Noir.  Ultimately, we all make our own decisions.

Comments

[Carol]

One thing I'd like to add is that I actually participated in the Portfolio Diet study in Vancouver, but in spite of a serious commitment to research, I had to withdraw after some weeks because I found the diet unnatural and seriously impossible to follow. The amounts of soluble fiber we had to eat were way out of the normal range, and made me feel quite ill, and the whole diet just didn't relate to real life eating in any way. Far better and simpler to go for the "fruit, veggies, whole grains and legumes" approach.

[Dr. G]

Contrary to the title of your blog entry, Dr. Jenkins did not find that MUFAs boost heart health, only that they raised HDLs and apolipoprotein AI. All of the implications about effects on heart health are speculated and unproven.

You also didn't mention the very long list of interest conflicts for the authors. It looks like Jenkins and Kendall have some serious financial ties to companies that profit from sales of products that contain MUFAs:

Dr. Jenkins is a consultant for Herbalife International, Nutritional Fundamentals for Health, Pacific Health Laboratories, Metagenics/Metaproteomics, Bayer Consumer Care, BENEO-Orafti, the Science Advisory Committee of Agriculture and Agri-food Canada, and the Canadian Agriculture Policy Institute and has received consulting fees from the Almond Board of California, the California Strawberry Commission, the Soy Advisory Board (Dean Foods), Kellogg Company, Quaker Oats, Procter & Gamble and Olways Preservation Trust. He holds grants from Solae, Unilever, Loblaws Supermarkets, Barilla, Haine Celestial, the Sanitarium Company and BENEO-Orafti and a board membership with Herbalife International and has stock options for Pacific Health Laboraties Inc. His wife is a director of Glycemic Index Laboratories, Toronto, Ontario. Dr. Kendall has received a grant from the Canadian Institutes for Health Research, travel support from the Almond Board of California and partial salary support from research grants provided by Loblaws.

[Healthy Librarian]

Dr. G,

My blog title was just being provocative & close to what the press releases said--and my attempt was to show that there was way more to the story. So I agree with you.

Yes, you are right--higher HDLs & apolipoprotein A1--do not necessarily translate into better heart health--and that was the point of writing my post. I'm guessing you did not read it through to the end, or you would have realized that.

Benecol, as far as I'm concerned is ridiculous product--plant sterols in margarine? If Jenkins wanted to use plant sterols, there are other non-fat ways of taking it.

But, you are right, I didn't even get into the conflicts of interest re this study--which was supported by the Canadian government. The authors have long list of "conflicts of interest"--including companies that produce oils, like Barilla & Haine Celestial--and of course the Almond, Strawberry, & Soy boards. I'm certainly glad to see these openly published.

[Bev]

I'm afraid the effect of this story might be that some people who don't read through to the end might think that adding oil is a good thing.

[Linda]

Thank you for this explanation. I saw the breaking news of this study on Science Daily this morning and started second guessing myself. I eat whole-food vegan, but not oil-free because I figure my lipids aren't hurting me--they are textbook for newborns according to my doc. But, the belly fat problem--that's the thing! You have me VERY interested, now that you say that cutting out the oil is eliminating belly fat you didn't even know you needed to lose. Love to see a recent picture of you here, as a motivator!

[Healthy Librarian]

Bev, you're right--I should have come right out & said what I thought at the start. You really had to read the "whole long thing" to realize that adding olive oil & nuts isn't such a good thing.

Linda, you're right--I do need to post a recent picture. Maybe this weekend. The bad thing is that I probably can't wear the strapless formal I planned to wear to a wedding in two weeks--it's way too loose!

[Barbara]

Great post!

I'm happy to side with Jeff Novick and Esselstyn for myself, and avoid nuts. I find them too addictive and easy to overdo anyway. But sometimes I wonder if worrying too much about the Omega 3 to 6 ratio in foods is just part of the American way of breaking everything down and studying it to death and ignoring the larger picture. I know Joel Fuhrman thinks they're very healthy:

"Almost all raw nuts and seeds are rich in micronutrients and protective food substances. They are not just a fat source, and they are also rich in plant proteins with favorable effects. We should aim to meet our requirements for both short and long-chain omega-3's, but it is healthy, not unhealthy, to get most of your fat intake from foods such as almonds and sunflower seeds which are rich in mono and polyunsaturared fats and micronutrient powerhouses, instead of extracted oils and animal products, which do not have comparable micronutrient density. This has already been well documented. It is good to consume a little ground flax seeds and walnuts daily because they are rich in those omega-3 fats that are otherwise low in the American diet that is overly rich in animal products (largely omega-6 and saturated fats)." http://www.diseaseproof.com/archives/healthy-food-nuts-and-seeds-are-excellent-foods.html

By the way, speaking of studying things to death, every time I come upon a reference to Lawrence Rudel's African Green Monkey study I am horrified anew. Those poor animals were kept captive for 5 years, and then slaughtered, just to look at their arteries. We have an overwhelming amount of evidence of the effects of diet on disease from the epidemiological studies and Esselstyn's study and and autopsies of humans, etc. etc. - it's really not necessary to torture another species for so little gain.

[Peter]

As you highlight the problem with oils and nuts is their density and how even a few nuts or a so called 'bit of oil' adds up in calories very quickly. I think most people would be surprised if they paid close attention to this fact.
I'll stick to the Esselstyn approach thank you. A large bowl of steaming oatmeal with fresh fruit is way more rewarding and of course filling compared to a handful of nuts.

[Healthy Librarian]

Carol,

Very interesting that you actually participated in the study--at least for awhile, that is. I agree with you--when you look at the list of foods in the diet, there is no way anyway could stand to do that for long. All those fake soy analogues, Metamucil twice a day, oat bran, and that horrible Benecol margarine. Yuck! I'd much rather eat whatever I want, and just leave out oil, dairy, and meat. Thanks for writing.

Barbara,

Re the nuts--if we were able to just eat a small amount I'm sure it would be just fine--but now that we no longer have to use a nutcracker & pick, it's so easy to just keep eating. And with all the various Nut Board's financed research, I also felt I was being so healthy when I'd easily eat 2 tbs of almond butter, + a Larabar, + nuts on top of ice cream, + nuts in my cereal, + a handful of nuts a day. Glad to leave it behind, and have just a few when it's called for in a recipe, or in an energy bar when I've exercised a lot. Re the green monkeys--that's why the study was only done once--and likely won't be repeated.

Other point, re Fuhrman, there are plenty of other foods that provide the same benefits as nuts, with less caloric-density, and high omega-6s. Hemp meal, for one.

Peter,

I know I was surprised about the whole calorie & omega-6 information when I first found out about it. Years ago, when I first heard of Esselstyn, I thought his elimination of nuts was extreme, and didn't make sense. Now I understand the rationale. It is surprising how easy it is to eliminate them, if needed if one has heart disease.

[Cynthia Bailey MD]

This is such an interesting topic, and I'm still on the fence. My story: I don't go crazy with oil but I have a very moderate amount of olive oil, canola and coconut. I also eat about 1 avocado a week and about 1/4 cup nuts a day. I'm 52, post menopausal and have always done moderate exercise regularly. My BMI is probably about 23. I drink occasional alcohol, mostly wine.

I just had my lipids measured and total cholesterol was 177 BUT HDL was 109. On my diet arthritis and inflammation stay down unless I 'suffer dietary indiscretions'. Granted it's anecdotal, but for me my choices seem to be working.

I think the key is doing what's right for our individual biochemistry and genetics. Some folks have a tough go of it with genetic heart disease or stroke, inflammatory conditions and lipid disorders. Their choices are harder than mine. The trick is to know what our body needs. My path is pretty much outlined in my posts on diet except I've never added that I totally avoid cow dairy products, which don't 'agree' with my body: http://www.otbskincare.com/blog/category/diet-nutrition/

Cynthia Bailey MD, Dermatologist

[Healthy Librarian]

Cynthia,

At the risk of sounding contradictory, I can agree with what you say. If you're feeling wonderful, weight is where it should be, and your lipids are as awesome as they are--it looks like your biochemistry & genetics can handle moderate amounts of olive oil, nuts, & avocados. Vogel & Rudel don't look at olive oil as the health-giving part of the Mediterranean diet--and Rudel's experience belied high HDLs, when they were elevated by olive oil. I read somewhere that alcoholics have HDLs, which makes one wonder if all HDLs are not created equal.

Of course, it's impossible to ever know what's really is going on inside of our blood vessels--so we use our own best judgment, and do what makes sense for each of us. In my case, eliminating the oil & nuts brought my weight & belly fat down to exactly where I want it to be--and without oil I can eat as much as I want without paying a bit a attention or counting calories. I get my fats from flax, chia, soy, & oats.