You Ask, I Answer: Polyunsaturated Oils

Have you ever heard of any danger in polyunsaturated vegetable oils from the way they are refined?

Mainly that they are already rancid [and bad for you] before they leave the factory?

What do you think?

-- Jade (last name withheld)
Istanbul, Turkey

Conventional refined oils undergo lengthy processes involving heat and chemical solvents.

In the case of polyunsaturated oils, this is mostly done to make them suitable for high-heat cooking (i.e.: deep frying) as they are easily degraded by heat in their unrefined state.

Several nutrition extremists online -- none of whom appear to have any nutrition credentials -- claim refined polyunsaturated oils are "cancer-causing."

Let's return to reality.

The issue with refined oils isn't so much that they are already rancid -- at some point in the processing, ascorbic acid (vitamin C) or tocopherols (vitamin E) are added to lengthen their shelf life -- but that they are nutritionally inferior to unrefined oils due to high amounts of phytonutrients and antioxidants being lost in the refining process.

This is why, when it comes to polyunsaturated fats, the recommendations are mainly to consume whole foods containing these heart-healthy oils (i.e.: nuts, seeds, fatty fish) as opposed to the oils themselves.

Unrefined polyunsaturated oils consumed at room temperature (i.e.: drizzling walnut oil over a salad) contain more antioxidants and phytonutrients than refined oils, but are still somewheat nutritionally inferior to whole foods.

Some Internet health extremists (the type who believe nutrition experts are part of a giant "conspiracy") go as far as saying that polyunsaturated fats are inherently unhealthy and unnecessary for human health. Quite a laughable claim, since Omega-3 and Omega-6 fatty acids (which we must get through diet since our our bodies can not produce them) are both polyunsaturated fats.

So while an unopened bottle of corn oil is not cancer-causing and rancid, there are better ways of adding polyunsaturated fats to your diet.

You Ask, I Answer: Battle of the "Diets"

Andy, are you going to blog about [the study that concluded that a low-carb diet was more successful at helping subjects achieve weight loss and healthier blood cholesterol profiles than Mediterranean or low-fat ones]?

-- Anonymous
Via the blog

I was most certainly planning on commenting on this study, mainly because of some very distracting flaws I noticed.

Let's begin with some basic information.

The study -- partially funded by the Robert and Veronica Atkins foundation (potential bias, anyone?) -- took place over 2 years, during which 85% of the 322 participants stuck with their respectively assigned diets (low-fat, Mediterranean, and low-carb.)

Now with some of my "uh, wait a minute" impressions.

Firstly, when it came to weight loss, low-carb beat out low-fat by 4 pounds (10.3 lbs vs 6.3 lbs), but edged out a Mediterranean Diet (which includes higher carbohydrate consumption) only by 0.3 lbs.

And although the low-carb diet resulted in the best blood cholesterol profiles, it's important to note that for this study, researchers "urged [the] dieters [on the low-carb diet] to choose vegetarian sources of fat and protein."

In other words, although the low-carbers had the highest saturated fat intake out of the three groups, the majority of their fats came from plant sources.

There isn't anything groundbreaking here. Anyone keeping up with nutrition research knows that mono and polyunsaturated fats are recommended for heart health.

Hence, this study calls into question the belief so many low-carb fanatics like Gary Taubes fervently hold on to -- that saturated fat is the best for blood cholesterol levels.

The study specifically mentions that the blood cholesterol levels of the low-carbers is due largely to the consumption of monounsaturated fats.

Besides, I always wondered why low-carb enthusiasts even bother bragging about improved cholesterol profiles on their diets when, two seconds later, they turn around and say that the cholesterol-heart disease link is a lie and the result of "bad science." Which is it?

The study wasn't entirely a "low carb diets RULE!" piece, either.

For instance, the Mediterranean Diet -- which was highest in fiber -- proved to be the most effective at managing blood glucose levels.

Yet again, this goes against traditional low-carb beliefs (and, once again, those Gary Taubes loves to pontificate) that the research on fiber is "inconclusive at best" and that there is no need to have it in the diet.

Before anyone jumps down my throat about whether or not I read Good Calories, Bad Calories, Gary Taubes himself said at his New York University talk in March of this year that he didn't think high-fiber grains were any healthier than refined ones.

Speaking of fiber, I noticed that the low-fat group was only asked to consume "low-fat grains."

This struck me as odd, mainly because it is hard to find grains high in fat -- they are all low-fat.

Additionally, it's hard to overlook some bias.

The study does not urge low-fat dieters to consume the healthiest grains (whole grains), yet specifically requests that low-carb dieters eat the healthiest fats.

I also found it strange that for the majority of this study the low-carb group was consuming 120 grams of carbs a day. This is definitely higher than the much lower levels recommended by most low-carb advocates.

Atkins, for instance, usually calls for no more than 100 grams of carbohydrates per day during the maintenance phase.

Finally, take a look at the numbers and you see that although the low-carb group was not calorie-restricted, their caloric intake was lower compared to their pre-study diet.

So, as always, we are talking about weight loss as a result of reduced caloric intake.

You Ask, I Answer: Vegetable Oil Spreads

My dad has heart disease, and his nutritionist said he should not use Earth Balance because it contains palm fruit (i.e., palm oil).

She instead recommends those spray bottles of fake butter.

Seems to me like that's recommending a bunch of fake chemicals instead of a naturally derived product with modest amounts of saturated fat (and no trans fat).

-- Anonymous
Via the blog

Hmmm.... that's rather peculiar advice.

The key with heart disease is limiting saturated fat, not eliminating it. Additionally, focus should be placed on consumption of healthier fats (monounsaturated and polyunsaturated.)

Besides, all oils contain some saturated fat -- it is virtually impossible to go an entire day without having some of it in our diets.

A tablespoon of olive oil, for instance, contains 2 grams of saturated fat (10% of a day's limit.) However, it also packs in 10 grams of heart-healthy monounsaturated fats.

A tablespoon of butter, meanwhile, provides 7.5 grams of saturated fat.

Earth Balance spreads have some saturated fat (naturally occurring in the plant oils from which it is made) but also 3.5 grams of monounsaturated fat and an additional 3.5 grams of polyunsaturated fat (440 milligrams are Omega-3 fatty acids).

Artificial butter sprays, meanwhile, are fat-free.

When it comes to heart disease, consumption of monounsaturated fat (olive oil, cashes, avocado, sesame seeds, peanuts, almonds, etc.) is much more beneficial than fat avoidance.

I say go for the Earth Balance (while still minding calories, of course.)

You Ask, I Answer: Saturated Fat

So is 30 to 35 percent total fat from calories a moderate-fat diet and above 35 percent a high-fat diet?

How much fat, as a percentage of total calories, do you think is safe to consume?

What do you see as the safe upper limit for total fat intake?

How much saturated fat can one consume with out risking clogged arteries?

-- David Brown
Kalispell, MT

Since we are talking about ranges, there is room for fluidity.

Here is how I break it down.

Anything below 15 percent of total calories from fat falls under the “very low fat” category.

I classify the range between 15 and 30 percent of total calories from fat as "low-fat" (with, say, 16 percent being closer to “very low in fat” and 29 being very close to “moderate”).

The 30 – 40 range is "moderate", and anything above 40 is "high".

What makes your question much more complex, though, is that fat is by no means a simple nutrient.

I can not simply throw out a figure and say, “Consume 35 percent of calories from fat” without giving additional detail.

For example, make most of those fats mono and polyunsaturated, aim for an Omega-6 to Omega-3 ratio no higher than 5:1, and avoid artificial trans fats (some animal meats naturally contain trans fats, which I am not worried about).

If someone's “35 percent of total calories from fat” is mainly comprised of trans fats, I would certainly not describe it as healthy intake.

That same percentage consisting of mainly mono and polyunsaturated fats, however, would get two thumbs up.

This shouldn't come as a big shock to regular readers of this blog.

Besides, does anybody seriously think four strips of bacon or a quarter cup of half and half are healthier than a grilled wild salmon steak or half an avocado?

As for your safe upper limit question: you won't find a technical "Upper Limit" (how much of a nutrient it takes to have detrimental, rather than beneficial, health effects) for saturated fat.

However, the 10 percent figure (which, as I will explain a little later in more detail, basically recommends that people consume no more than 10 percent of total calories from saturated fat) serves as an Upper Limit.

Thereby, intakes of, say, 40 percent have not shown to be beneficial to health.

One main problem with mainstream talk about nutrition is that it oversimplifies nutrients, especially fats and carbohydrates.

After all, a carb is not a carb is not a carb. Oatmeal, bananas, and baked potatoes are very different from donuts and Jolly Ranchers.

The first three provide fiber, vitamins, minerals, and phytochemicals. The last two are virtually empty calories.

This is why I strongly oppose blanket statements like, "carbs are bad." Really?

You mean to tell me that fruits, vegetables, and whole grains are no different than a cupcake?

It is also important to place nutrients in the right context.

Sports nutritionists and exercise physiologists agree, based on evidence-based research, that easily digestible carbohydrates that would normally not be outright recommended as highly nutritious (ie: white rice) can serve an important purpose after a strenuous workout.

Forego carbs after a very intense, long workout and glycogen stores are not fully restored. This is problematic, as it may result in the breakdown of muscle.

As for how much saturated fat someone can consume without risking clogged arteries, you have to, once again, frame it in the appropriate context.

I stand by the “make no more than ten percent of your total calories saturated fat” rule, but keep in mind this is over a period of time.

Let’s assume you eat 2,500 calories a day.

Ten percent of 2500 calories = 250 calories.

Divide 250 calories by 9 (the amount of calories per gram of fat) and you get 27.7.

So, you should get no more than 28 grams of saturated fat a day.

Does this mean that downing 40 grams at a birthday dinner is going to send you into coronary hell? Not at all.

What matters, as I always like to mention, are general patterns.

If you generally stay within that 10 percent figure, your risk is lowered.

If, however, the norm is 30 percent (in this case, 83 grams of saturated fat a day) for five, ten, or fifteen years, you will very likely run into problems.

You Ask, I Answer: Saturated Fat

You mentioned that saturated fat is the "bad" fat and this definitely is the common understanding these days.

Have you read any conflicting evidence about this?

After reading the first half of Gary Taubes' Good Calories, Bad Calories I came to the conclusion that saturated fat really isn't a big deal unless you're in the extreme heart disease risk category, which, at 27 and with normal cholesterol levels, I don't think I am.

And, while I don't agree with Taubes' anti-carb approach, I found his evidence about regarding the fat-cholesterol link (and how research was so highly influenced by politics, guesswork, and some key personalities) very interesting, and moderately convincing.

It seems that cholesterol levels are only veeery minimally affected by saturated fat in one's diet.

I'm wondering how you feel about this aspect of his argument, or if you've seen other people calling the evilness of saturated fat into question recently.

I thought I had it all figured out, but this is the one thing I'm still not sure about.

Thanks so much.

-- Meredith (last name unknown)
Via the blog

Gary Taubes is certainly not the first -- or only -- person to question the saturated fat/heart disease connection.

Although some studies date as far back as the 1950s, Mr. Robert C. Atkins brought the research out of the scientific community and into the mainstream.

He -- along with his proteges -- claimed that eating endless amounts of steaks, butter, and bacon actually led to healthier lipid profiles than low-fat, high-carb diets.

And so we come back to the issue of flawed logic. Let me explain.

Like Atkins, Taubes and his ilk approach this scenario from a very narrow "black or white" perspective.

Firstly, they are quick to judge detractors as low-fat advocates.

This is grossly inaccurate. For instance, I strongly disagree with Taubes, but a quick browse through this blog makes it clear I do not advocate low-fat diets.

Instead, I believe that an adequate amount of the right fats is crucial for our health.

I fail to understand why Taubes and his supporters practically worship saturated fat but completely fail to mention the health benefits of monounsaturated fats and omega-3 fatty acids.

They aren't saying "fat is healthy; make sure to include almonds, olive oil, and wild salmon in your diet!" Instead, they pretty much push red meat and bacon.

Mind you, current guidelines do not call for a complete elimination of saturated fat from the diet; they simply suggest no more than 20 grams a day (assuming a daily intake of 2,000 calories).

Many dietitians -- myself included -- recommend a low intake of saturated fat, but simultaneously urge people to seek out the healthy fats found primarily in salmon, olive oil, walnuts, flaxseed, and avocados.

Although there are some professionals who advocate very low-fat diets -- Dean Ornish comes to mind -- many of the dietitians I know do not support skimping on healthy fats.

Now, when you compare a high-fat (in this case, saturated fat) low-carb diet to a high-carb (conveniently, high in refined carbohydrate), low-fat diet, the high-fat diet will lead to a better lipid profile (triglycerides, for instance, are related to refined carbohydrate intake, not dietary fat).

This, however, is misleading.

It's akin to only comparing bronze (diet high in refined carbohydrates and low in fat) and silver (diet high in fat, albeit saturated, but low in refined carbohydrates) and claiming silver to be the most expensive metal.

Yes, the most expensive of the two.

But, bring in platinum (a diet low in saturated fat but high in mono unsaturated fats and whole grains) and suddenly silver doesn't look quite as amazing.

I would like Gary Taubes to compare two high-fat diets (one high in saturated fats, one high in mono and polyunsaturated fats) and conclude, with a straight face, that the saturated fat-rich one is the healthiest.

There are literally hundreds of human clinical research studies showing a correlation between saturated fat intake and heightened coronary heart disease risk.

One interesting one was published in the July 2005 edition of the British Medical Journal.

Turns out that, in 1991, the Polish government stopped subsidising foods high in saturated fat.

Eleven years later, "deaths from coronary heart disease had dropped by over a third in the 45-64 age group - a 38 per cent drop for men and 42% for women."

During this time, saturated fat consumption fell by 7 percent, and -- more importantly -- polyunsaturated fat consumption increased by 57 percent!

We again come back to the notion that the key is not in reducing total fat intake, but in replacing saturated fats with healthier varieties.

Taubes happily bashes anyone recommending a low-fat diet, but what are his arguments against replacing saturated fats with Omega-3 fatty acids (a type of polyunsaturated fat) for improved lipid profiles?

Moving on to red meat, there is also a good deal of research showing that colon cancer risk is indeed affected by red meat consumption (this 2006 meta-analysis from the Pakistan Journal of Nutrition summarizes some major findings well).

A great Italian study by Talvani et al in 2000 also looked at red meat intake and cancer risk.

I recall Mr. Taubes scoffing and referring to all this evidence as "questionable" when he was on Charlie Rose several years ago.

How he came to that conclusion I do not know.

In my mind, sanctifying saturated fat and telling people to eat it liberally is irresponsible.

By the way, this idea that advice to eat less red meat is some sort of conspiracy relating to politics is rather laughable since, as Marion Nestle brilliantly explains in Food Politics, the national beef association threw a major hissy fit when Dietary Guidelines originally urged the public to simply "consume less red meat".

They were quickly changed to "choose lean cuts of meat," so as to not offend the powerful beef lobby.

We come back, as always, to the issue of moderation.

Have a slice of Swiss cheese here and there or pour a splash of whole milk into your morning coffee if it makes you happy; just don't make saturated fats the main players of your diet.

A Doctor's Delicious Orders

Dr. Andrew Weil is a renowned name in the field of nutrition who focuses on integrative nutrition (mainly the idea that food's healing properties are a more effective option than that of most over the counter medications) and its role in overall wellness.

Yesterday I was at Whole Foods browsing the food bar section and after picking out my usual (Clif Nectar chocolate walnut bars, Lara key lime pie bars, Pure chocolate brownie bars), I spotted a new product -- Nature Path's Dr. Weil's pure fruit and nut bars.

The banana manna flavor caught my eye. Three ingredients (organic dates, organic dried bananas, and organic almonds), 180 calories, four grams of fiber, sodium-free, no added sugars of any kind, six grams of heart-healthy fats, and ten percent of the daily potassium recommendation!

There are four other flavors, including pistachio-nut and chocolate-coconut.

By the way, chocolate-flavored fruit and nut bars are a great way to indulge a chocolate craving.

They contain pure cocoa, which is naturally sugar-free and provides an intense taste comparable to that of conventional dark chocolate.

I always make sure to have some in my office desk drawer and my backpack.

Numbers Game: Answer

Which of the following provides the highest amount of omega-3 fatty acids?

a) 4 ounces of fresh cold-water salmon
b) 4 ounces of canned sardines (in oil)
c) 4 ounces of fresh lobster
d) 4 ounces of canned salmon
e) Trick question. They all provide the same amount!

The correct answer is "d" -- canned salmon. Four ounces pack in 2.2 grams of Omega-3 fatty acids!

The remaining fish?

4 ounces of fresh cold-water salmon provide 1.7 grams, sardines contribute 1.8 grams, and fresh lobster contains 0.1 grams.

Omega-3's are essential (meaning our bodies can not produce them) polyunsaturated fatty acids that have been linked in hundreds of studies to lower risks of heart disease, cancers, rheumatoid arthritis, and even Alzheimer's and Parkinson's.

Recommendations are currently set at 1 to 2 grams a day (or 7 - 14 grams a week).

Why does canned salmon edge out cold-water salmon? Simple -- all canned salmon is wild.

The figure for cold-water salmon, meanwhile, is an average that takes into account wild and farmed salmon.

Farmed salmon offers lower levels of Omega-3 fatty acids since they are fed grains (rather than subsisting on a natural diet of small marine creatures).

Although all salmon is a great source of Vitamin D (four ounces provide a day's worth!), canned salmon offers an additional bonus -- calcium. Turns out the cooking process softens the bones to such a degree that they can be eaten.

The result? A quarter of your day's calcium needs in a (lactose-free) four-ounce piece!

ADA Conference: Define "Great"

Frito-Lay had the following sign you see on your right at their stand (in case you can't quite make it out, the first sentence reads, "Frito-Lay chips are a great way to add healthier oils to the diet.") at the ADA's Food and Nutrition Conference Expo.

A "great" way? I think the marketing team got a little carried away.

While their products do contain healthy fats, they aren't exactly a nutrition powerhouse (offering a measly 1 gram of fiber per serving and not much in terms of vitamins and minerals, except for their potato chips, which contain a fair amount of potassium).

I could think of better ways to get heart-healthy fats -- avocados, almonds, walnuts, peanuts, sunflower seeds, tempeh, tofu, salmon, tuna, and flaxseed, to name a few.

Adding avocado slices to a salad, or some ground flaxseed to a smoothie truly are great ways to add healthy fats to your diet, since they also contribute vitamins and minerals.

Besides, this sign is making a confusing claim. Notice that the terminology isn't "healthier fats" (ie: chips containing vegetable oils rather than something friend in animal fat or butter), but rather "healthier oils." Huh?

What exactly is an "unhealthy oil"? I can think of unhealthy fats, like lard and butter (none of which are oils), but despite there being some oils (i.e.: olive oil) that are heart-healthier than others, I can't think of one I would categorize as unhealthy.

Enjoying a handful of Tostitos is far from being a nutrition no-no, but if someone needs to incorporate heart-healthy fats into their diet, chips are far from the first thing I would recommend.