| | Interviews with Nutritional Experts: Health Risks from Processed Foods and Trans Fats: Part II | |
Interview with Dr. Mary Enig
as interviewed by Richard A. Passwater PhD
Mary G. Enig, PH.D., a nutritionist widely known for her research on the
nutritional aspects of fats and oils, is a consultant, clinician, and the
Director of the Nutritional Sciences Division of Enig Associates, Inc.,
Silver Spring, Maryland. She received her PhD in Nutritional Sciences from
the University of Maryland, College Park in 1984, taught a graduate course
in nutrient- drug interactions for the University's Graduate Program in
Nutritional Sciences, and held a Faculty Research Associateship from 1984
through 1991 with the Lipids Research Group in the Department of Chemistry
and Biochemistry. Dr. Enig is a Fellow of the American College of Nutrition,
and a member of the American Institute of Nutrition. Her many years of experience
as a "bench chemist" in the analysis of food fats and oils, provides
a foundation for her active roles in food labeling and composition issues
at the federal and state levels.
Dr. Enig is a Consulting Editor to the "Journal of the American College
of Nutrition" and formerly served as a Contributing Editor to "Clinical
Nutrition." She has published 14 scientific papers on the subject of
food fats and oils, several chapters on nutrition for books, and presented
over 35 scientific papers on food and nutrition topics. She is the President
of the Maryland Nutritionists Association, past President of the Coalition
of Nutritionists of Maryland and was appointed by the Governor in 1986 to
the Maryland State Advisory Council on Nutrition and served as the Chairman
of the Health Subcommittee until the Council was disbanded in 1988.
Last month we talked mostly about what trans fats (TFAs) were, how they
interfere with "machinery" of our normal cell biology and that
they are a recent and unnatural intrusion into our diets. In Part II, we
will look into the health problems caused by TFAs, and in Part III, Dr.
Enig will put the research on TFAs and other fats in perspective and give
us her thoughts on the pluses and negatives of the Health Food Industry
as seen from academia.
Passwater: You mentioned the your research was stimulated by the early investigations
of Drs. Fred Kummerow, George Mann and Edward Pinckney. What did you set
out to investigate and what have others added to these findings?
Enig: Much of the Trans- Fatty Acid (TFA) research that was accomplished
at the University of Maryland from 1977 to today was done to answer some
very basic questions. For example, we wanted to know how much TFAs people
were being exposed to. So during some of the early research, we measured
the amounts of TFAs in typical U. S. foods and then estimated the amounts
in various diets and in the food supply.
The next set of efforts was done to measure the effects that feeding diets
containing physiologically relevant amounts of TFAs to laboratory animals
had on some reproductive and lactation functions, on the alteration of membrane
properties, and on the consequent alteration of enzyme functions that had
physiological importance. These different efforts were measured by our research
group, and many of our findings, e. g., that the enzyme functions were adversely
affected, were repeated by various other research groups. It is hard to
tell sometimes if we were repeating the findings of others or if others
were repeating our findings. I think it is safe to say that the research
was invariably reproducible as long as the same animal model and the same
amount of TFAs were used. In other words, our findings were real and other
researchers could easily find the same thing.
A number of research groups were able to use some of our basic findings,
and many of the researchers were using their own models and their research
was providing information that was parallel and complementary to ours. In
many instances, the other research teams had access to better funding and
models that we did not have at the University of Maryland.
One research group at Auburn University examined diets of adolescent girls
and directly measured the TFAs in their diets by laboratory analytical methods.
[16, 17] They found that approximately two- thirds of the TFAs in the diets
of these adolescents could be predicted by the food composition data in
our 1983 research paper for 220 foods. This is rather remarkable since their
research was done in another part of the country. It does show the similarity
of many of the same types of partially hydrogenated fats in diets across
the U. S.
A research group at Louisiana State University studied, among other things,
the effects of TFAs on what is called "the second messenger,"
cyclic AMP and the digitalis receptor. [18] They found that TFAs affected
both.
Still another research group, this one at Virginia Polytechnic Institute,
studied the effect of TFAs on bone development. [19, 20] Their research
showed some very undesirable effects! AS far as I know, the latter two groups
who were finding important effects have not been able to continue because
of lack of funds for TFA research. Their efforts were done independent of
our concerns and findings but parallel to our efforts.
There have been a number of other research efforts that have been given
widespread publicity. These include the published findings from Dr. Martijn
Katan's lab in Holland that the TFAs lower the "good" High- Density
Lipoprotein (HDL) and raise the "bad" lipoprotein [a] (Lpa) which
is atherogenic. [21] Also, the published findings from Dr. Walter Willett's
research at Harvard on 85,000 nurses, as well as other prospective studies,
have showed that those people who consumed the most TFAs had the most heart
disease. [3] Dr. Willett's group also has preliminary, as yet unpublished,
data that those individuals who developed breast and prostate cancer had
higher intakes of TFAs. These findings have been presented at scientific
meetings by Dr. Willett and his staff.
I have recently prepared a technical report which includes additional information
that would normally not be found in typical scientific reviews. [22] This
information is of special interest to many in the food industry and the
regulatory agencies. The report identifies all of the different research
groups that have been working on TFAs around the world over the past 60
years.
Passwater: I remember how the processed food industry tried to suppress
your early research. As Rodney Leonard, the editor of Nutrition Week noted,
you fought tenaciously to bring out the truth and were "a burr under
the saddle of the [processed food] industry and the government, persistently
challenging the contention that the health threat of trans fatty acids is
overplayed and that the current level of consumption poses no threat to
public health." Most of those who were skeptical then have examined
the steady stream of new data and now agree with you that TFAs are a major
health threat. How were you able to keep on? What techniques were used against
you and how did you overcome them? Where did you find moral and scientific
support?
Enig: As you know from some of our past conversations, we ran into some
strong challenges from certain segments of the edible oil industry regarding
our findings. In addition to writing several articles to "refute"
our findings, and seeing to it that our major reports did not get properly
referenced, those individuals who actively opposed our research were able
to influence funding sources. Gradually though, other researchers started
to realize that we were correct and appropriately conservative in our approach
to research, and consequently, most of the "bad- mouthing" that
we encountered has backfired.
Passwater: Yes, I remember well how we were both encountering difficulties
with "the establishment." I am happy to note, as you well know,
that the same is happening regarding my findings regarding vitamin E and
the prevention of heart disease, and of the antioxidant nutrients in the
prevention of cancer. We never did get the funding needed to further pursue
our research.
Enig: You're right. At the University of Maryland we never did get the type
of funding that you need to receive to continue the level of research that
would have been desirable, but what funding we did receive was carefully
managed and many of the people in our research group were dedicated to the
research.
I think we found moral support because we knew we were scientifically correct,
and ultimately the scientific support came as other researchers started
to evaluate the problems without having certain industry people set up their
research protocol. AS you realize from your years of involvement in research,
good research properly done is always reproducible, if all the variables
are the same, but it is also possible for unscrupulous individuals to set
up a research protocol designed to obfuscate, and if that gets published,
it keeps other good researchers from continuing to work in the area. Frequently,
those individuals who are coopted write their summary and abstract the way
the industry wants them to, but they usually leave their data intact so
that a knowledgeable researcher can recognize the inconsistency. However,
it is a very time- consuming task to constantly challenge each piece of
misinformation that you see.
Passwater: Yes, it is a difficult task, but you and I give it our best shots.
In the past we did a lot of challenging others to prove us wrong, and now
we can smile a lot.
Enig: Our work is not done yet! There is still much to do.
Passwater: Right again! How big is the problem with TFAs? How extensive
are trans fats in our modern diets, and how does this compare to ancient
diets and other diets around the world.
Enig: Today the levels of TFAs vary around the world from practically zero
to levels much like those found in our foods in the U. S. It depends on
how much partially hydrogenated vegetable fats or partially hydrogenated
marine oils are present in the food supply.
Without the commercial partial hydrogenation process, as would have been
the case more than a hundred years ago, the levels of TFAs in diets would
be relatively low. Only the ruminant fats would have supplied any, and the
types of isomers that are found in the ruminant fats behave in a very different
way from those found in the partially hydrogenated vegetable oils. Additionally,
the research shows that the TFAs are more of a problem when the level of
saturated fat is low. Diets that are higher in ruminant fats are also higher
in saturated fats. Most ruminant fats have about 2- 3% TFAs whereas the
partially hydrogenated vegetable fats are commonly 30- 40% and as high as
53% in foods in this country.
After analyzing hundreds of food samples for TFAs, chemically analyzing
food composites, and calculating dietary information, I am confident that
there are many people in this country who consume 20% of the total fat in
their diet as TFAs. On average though, 10.9% is the number we came up with
when we looked at all of the published analyses. The typical french fried
potatoes are around 40% TFAs, and many popular cookies and crackers range
from 30 to 50% TFAs, and every donut I have analyzed has about 35 to 40%
TFAs. Since these are all fairly high fat products, someone who eats a lot
of these types of foods will get a large amount of TFAs. Several years ago,
we documented nearly 60 grams of TFAs in someone's typical daily diet.
Passwater: Wow! I hope that's no one I know. Dr. Enig, you mentioned that
TFAs are atherogenic - - that is they cause atherosclerosis. Then you mention
that TFAs are more of a problem when saturated fats are low. Yet most people
fear saturated fats because they have been told that it is the saturated
fats that cause heart disease.
You are recognized as a leading expert on fats and oils, do saturated fats
cause heart disease?
Enig: The idea that saturated fats cause heart disease is completely wrong,
but the statement has been "published" so many times over the
last three or more decades that it is very difficult to convince people
otherwise unless they are willing to take the time to read and learn what
all the economic and political factors were that produced the anti- saturated
fat agenda.
Periodically, various reports have come out that show the inconsistencies
in the theory. You have already discussed this with the well- known cholesterol
and lipids researcher, Dr. David Kritchevsky of the Wistar Institute. [23]
In 1977, Dr. Kritchevsky noted that it did not make any difference what
kind of fat was added to the whole foods diets in animal studies - - only
when the diets were very unnatural chemically could changes be brought about
- - and from study to study these changes were inconsistent. [24]
As you frequently report, the latest theories regarding heart disease point
to oxidized fats and oxidized lipoproteins as culprits. This being the case,
accusations against chemically- stable, basically non- oxidizable saturated
fat don't make sense. Most people who find fault with saturated fats do
not really understand that our cells are busy making saturated fatty acids
all the time from carbohydrates and excess protein.
Passwater: Do tropical oils cause heart disease?
Enig: No they don't. Several studies have shown that there is no increase
in heart disease in countries or communities where most of the fat is either
coconut oil or palm oil. Palm oil that is not extensively refined has very
high levels of antioxidants, and coconut oil has high levels of very useful
medium chain fatty acids. There are many older research studies that showed
that adding quite a bit of coconut oil to the diet of persons having high
blood cholesterol reduced their level of cholesterol. Dr. George Blackburn
from Harvard Medical School has written an extensive review on this topic.
[25]
It is unfortunate that this misinformation about these oils became so widespread
because they are very stable oils that have unique functional properties
and products made with them as the fat component usually have far less fat
and therefore fewer calories. Needless to say, they would also have virtually
no TFAs which are unquestionably atherogenic. When coconut oil was used
in the manufacture of crackers, very little fat was added to each cracker,
but the crackers did not become stale before they could be purchased. Now
the fat- free crackers become very stale very quickly, and the crackers
made with the more unsaturated oils are higher in fat and are greasy or
they appear drier because they are made with the high- temperature melting
partially hydrogenated oils. Deep fried foods made in these oils never absorb
quite as much fat as they do when they are fried with the more unsaturated
oils.
Passwater: Speaking of deep fried french fries, I notice that the Community
Nutrition Institute is pleading with McDonald's to go back to their old
cooking oil, an animal tallow. CNI cited higher risks of coronary heart
disease, coronary artery disease, and low birth- weight babies due to the
partially hydrogenated vegetable oil that McDonald's has been using since
1990. [26]
Enig: Yes, when I analyzed the oils, I found that the percentage of fat
that was saturated fat in their french fries dropped from 49% to 24% when
McDonald's switched from animal tallow to partially hydrogenated vegetable
oil. But the percentage of fat that was TFAs rose from 5% to 42- 48%. McDonald's
own study showed that the total amount of fat in its fries rose from 17.6%
to 27.9% Recently, McDonald's has again switched to an oil that has cut
the TFAs in half. But, those who insist on eating french fries were better
off when the beef tallow was used.
Passwater: Why were earlier researchers misled about saturated fats and
heart disease?
Enig: The simplistic, abbreviated story of how some of the anti- saturated
fat rhetoric got started and then took a strangle hold, is that when laboratory
animals were fed semi- purified and artificially saturated (fat) diets,
the animals actually became deficient in essential fatty acids. As a result,
these animals developed lesions that were incorrectly defined as the equivalent
of heart disease. This "research" was touted as showing an effect
of "saturated" fat. Then when Dr. Ancel Keys of the University
of Minnesota reported that hydrogenated fats were responsible for heart
disease [15], the response from the threatened edible oil industry was to
claim that it was only the saturated fats that were the culprits, and that
the industry would get rid of the problem by only partially hydrogenating
the oils. From that point on, the saturated fats stood "guilty as accused,"
even though study after study showed that there was no relationship between
saturated fat intake and the development of heart disease.
In fact, some of the studies showed that there was less progression of the
disease process when the saturated component was higher. [27] Usually the
proponents of the lipid hypothesis managed to squelch the effect of these
reports. Of course the partially hydrogenated oils were really very little
different in saturated fat level than the fats and oils that had been called
"hydrogenated," but the public and the media and many of the naive
researchers didn't know that.
As time went on, the whole heart disease agenda became a multi- million
dollar business that was benefiting the researchers funded by the part of
the National Institutes of Health that deals with heart disease, the National
Heart, Lung and Blood Institute. The only people not benefiting were and
are the consumers who are continuing to get more and more heart disease
at higher and higher costs. The consumer may not be dying from heart disease
as often as they were 30 years ago, but they are undergoing more surgery
such as by- pass and angioplasty, and they are swallowing more expensive
cholesterol- lowering drugs. All in all, while the so- called mortality
figures have decreased, the incidence has greatly increased.
Of course, the ill- trained consumer activist groups have added to the problem
by continuing to publish their own misinterpretations of the science, and
this in turn, is further publicized in the media.
Passwater: Well, I see that you haven't backed off and cow- towed to the
consensus pseudo- scientists that form opinions without looking closely
at the data. I would like you to explain the real facts and their proper
interpretation for the benefit of our readers. So let's look at fats and
cholesterol, TFAs and the obesity trigger, and your thoughts on helping
the Health Food Industry in Part III.
"Health Risks from Processed Foods and Trans Fats: Part III"
| Richard A. Passwater, Ph.D. has been a research biochemist since 1959. His first areas of research was in the development of pharmaceuticals and analytical chemistry. His laboratory research led to his discovery of......more |  |
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