Unsaturated Fats 

By Lita Lee, Ph.D. 


Original PDF file is to be found here.

The following information comes mainly from the research of Dr. Ray
Peat, who has gathered hundreds of scientific references, which document
compelling laboratory data to show that excessive amounts of unsaturated
oils are dangerous to your health. Other researchers are mentioned when

"An excess of the polyunsaturated fats (PUFA's) is central to the
development of degenerative diseases: cancer, heart disease, arthritis,
immunodeficiency, diabetes, hypertension, osteoporosis, connective
tissue disease, and calcification." (Peat) 


Unsaturated oil: one that contains double bonds because it lacks
hydrogen atoms. Polyunsaturated oils contain more than one double bond.
They are also called polyunsaturated fatty acids or PUFA's and sometimes
"essential fatty acids." These include: soybean, corn, safflower,
canola, sesame seed, nut (peanut, walnut, almond, etc.), flaxseed, fish
(salmon, cod liver), Evening Primrose and Borage oils. All unsaturated
oils contain some omega - 6 acid, called linoleic and some omega-3 acid,
called linolenic acid. Linoleic acid is the precursor of gamma-linolenic
acid or GLA. Linolenic acid is the precursor of Eicosapentaenoic acid or
EPA, which then converts to Docosahexenoic acid or DHA. I am putting
down these chemicals because many people think they are avoiding
unsaturated oils while taking omega-6 and omega-3 oils, or GLA, EPA and

Partially hydrogenated oils (margarine): the chemical addition of
hydrogen to saturate the double bonds and cause the oil to become solid,
to mimic butter. 

Peat wonders if there is a threshhold limit of unsaturated fats, above
which the deleterious health effects occur. No one knows. Since no one
knows, I recommend avoidance of all unsaturated oils, that is, oils that
are liquid at room temperature, whether processed, cold pressed or
unrefined, except extra virgin olive oil. 

Since all plants contain unsaturated oils except fruits and fruit
juices, it is impossible to avoid them. However, the fiber in plants
offers some protection against the toxicity of these oils. Don't think
you avoid unsaturated fats if you eat commercial meat because commercial
animals are fed soybeans and corn, both high in unsaturated fats, so
even the so-called saturated fat in commercial meat is highly
unsaturated (30% or more). There is no group of people whose diet does
not contain unsaturated fats. 

Are unsaturated fats really essential? 

Is it rational to talk about substances, which we cannot avoid no matter
how hard we try as being essential? PUFA's are present in all plants
(seeds, nuts, grains, beans, vegetables, etc.) except fruits. Peat
questions that unsaturated oils are essential (which means we have to
eat them because we can't make them). Why? Humans and animals contain
desaturase enzymes, which can produce unsaturated fats from oleic and
palmitoleic acids when deprived of the so-called essential fatty acids. 

No one has ever given correct physiological evidence that these PUFA's
are, in fact, essential. During the last 10 years many journal articles
have reported that the body makes its own brand of unsaturated oils in
people who don't eat the exogenous ones. PUFA's poison the enzymes
inside your body that are necessary for the production of unsaturated

How unsaturated fats inhibit enzymes and cause immune suppression 

According to Peat, excessive unsaturated fats inhibit all body systems,
mainly by inhibiting enzymes essential to metabolic processes required
for health and immune protection. Here are some examples. Unsaturated
fats directly kill white blood cells. 

Unsaturated oils inhibit proteolytic enzymes and this has far-reaching
effects. Inhibition of proteolytic enzymes by unsaturated fats causes
trouble at many sites where proteolytic enzymes are necessary: the
digestion of dietary protein, the digestion of clots, the digestion of
the colloidal protein released by the thyroid gland which leads to the
active thyroid hormone, and the digestion of cellular proteins involved
in maintaining a steady state as new proteins are formed in the cell. 

There is an enzyme system called the protein kinase C (PKC) system that
is excessively activated by certain substances and certain conditions.
Substances that cause excess activation of this system are: PUFA's,
including free linoleic and linolenic acids, excess estrogen (a cancer
promoter) and cancer promoting phorbol esters. These substances
stimulate the cell while blocking the energy it needs to respond. The
PKC system is also abnormally activated in diabetes and cancer.
Unsaturated fats cause thyroid suppression and lead to hormonal
imbalances Unsaturated oils block thyroid hormone secretion, its
circulation and its tissue response. This leads to increased estrogen
levels. Since thyroid hormone is essential for making the anti-aging
hormones, namely pregnenolone, progesterone and DHEA, when your thyroid
is in trouble, the manufacture of these anti-aging steroids are in
trouble. Also, since thyroid converts cholesterol in your body to these
anti- aging steroids, low thyroid function can lead to high cholesterol.

Unsaturated oils inhibit cellular respiration 

Mitochondria contain some unsaturated fats to allow them to take up
water. The body contains enzymes to make just the right amount needed
but this makes mitochondria very susceptible to free radical damage AND
to the damage of dietary unsaturated oils. All toxins are enzyme
poisons. Dietary unsaturated fats suppress the enzymes that make in vivo
unsaturated fats. Therefore, unsaturated fats are, by definition, toxic.

Ephraim Racker observed that free unsaturated fatty acids (PUFA'S)
inhibit mitochondrial respiration (the mitochondria are the "lungs" of
the cell) - the cell has trouble breathing. 

Stress and hypoxia (oxygen deprivation) cause cells to take up large
amounts of unsaturated fatty acids where they can directly damage
mitochondria. Thus, large amounts of stored unsaturated fats may present
a real danger to the stressed person (Peat). This is especially true in
people who have cancer, because cancer cells are known to have a high
level of unsaturated fats. 

Unsaturated oils and diabetes 

I have a client with type I (insulin-dependent) diabetes who has a
terrible time controlling her blood sugar. Discussing her case with
Peat, he asked me whether or not she ate unsaturated oils. Why? Because
research indicates they are implicated in diabetes. I asked her what
oils she used in her cooking. She answered, "safflower oil." 

Carlson (1966) suggested that increased circulating PUFA's can block the
Krebs cycle, resulting in insulin resistance from prolonged pancreatic
stimulation. Recently, Ikemoto, et al, showed that a high safflower oil
diet was found to cause diabetes.6 Taken together, these studies suggest
that the unsaturated fats are involved in the process of producing

To illustrate, in 1947, B.A. Houssay [7] found that a diet based on
sugar as a source of energy was more protective against diabetes than a
diet based upon lard, while the most protective diet was based on
coconut oil. Essentially, he showed that the unsaturated (pork) fat
permits diabetes to develop, sugar is slightly protective and coconut
oil is very protective against the form of diabetes caused by a poison
(unsaturated oils). Coconut oil increases the metabolic rate, apparently
by normalizing thyroid function. Coconut oil provides energy to
stabilize blood sugar while protecting mitochondria and the thyroid
system from the harmful effects of unsaturated fats. 

Similarity of estrogen and unsaturated fats: promote aging and disease 

PUFA'S are similar to estrogen. The information that PUFA's and estrogen
act similarly on the same regulatory pathway is important. Both inhibit
thyroid function, inhibit vitamin E, promote age spots (lipofuscin),
promote clot formation, promote seizures, and impair brain development
and learning. Estrogen, found in birth control pills and in ERT
increases secretion of growth hormone, which, in turn, causes an
increase in free unsaturated fatty acids in the blood. 

These parallel functions suggest that the role of PUFA's and estrogen in
reproduction may be similar, namely the promotion of cell division,
essential for reproduction but dangerous in abnormal cell division, such
as cancer. Says Peat, "if a certain small amount of dietary PUFA is
essential for reproduction, but for no other life function, then it is
analogous to the brief estrogen surge, which must quickly be balanced by
opposing hormones," (such as progesterone). 

Immunosuppression of unsaturated oils 

Intravenous feeding with unsaturated fats is so powerfully
immunosuppressive that it is now advocated as a way to prevent graft
rejection (Mascioli, E., 1987). The poisonous effect of unsaturated
fatty acids on the immune system has led to the development of new
intravenous feeding products containing short and medium-chain saturated
fats (Hashim, S., 1987). [8] 

Stress and hypoxia (oxygen deprivation) can cause cells to absorb large
amounts of unsaturated fatty acids. It is well known that cancer cells
are dependent on unsaturated fatty acids for life and growth. 

Cardiotoxicity of unsaturated oils 

There is well-established research indicating that excess unsaturated
fats are cardiotoxic. [9,10,11,12] Since stress increases the amount of
unsaturated fats and peroxides in the blood and in the heart, stored
unsaturated fats may present a special danger to the stressed organism. 

Recently, Kramer (1982) [13] found that the cardiac necrosis (tissue
death) caused by unsaturated fats, especially linolenic acid, could be
prevented by coconut oil. Does this mean that saturated fats are
essential? Maybe not, since the animal or human organism can normally
produce enough saturated fat from dietary carbohydrate or protein to
prevent cardiac necrosis UNLESS the diet is too high in unsaturated

Unsaturated fats are essential for cancer 

In 1927, Bernstein and Elias observed that a low unsaturated fat diet
prevented the development of spontaneous tumors. [14] Subsequent
researchers have observed that unsaturated fats are essential for the
growth of tumors. [15,16, 17] According to Kitada et al. (1987) [18],
tumors secrete a factor, which mobilizes unsaturated fats from storage,
thus guaranteeing their supply in abundance until the fat tissues are
depleted. In some experiments, the carcinogenic action of unsaturated
fats was offset by adding thyroid glandular. [19] This observation
suggests that at least part of the effect of unsaturated oils is to
inhibit thyroid function. 

Ip et al. (1985) [16] studied the relationship of carcinogenicity to the
percent of unsaturated fats ranging from 0.5% to 10%. His results show
that the optimum unsaturated fat intake may be 0.5% or less. In addition
to inhibiting the thyroid gland, unsaturated fats impair intercellular
communication, [20] suppress several immune functions related to cancer,
and are present at high concentrations in cancer cells, where their
antiproteolytic action would be expected to interfere with the
proteolytic enzymes and to shift the equilibrium toward growth. Even
though cancer cells are known to have a high level of unsaturated fats,
[21] they have a low level of lipid peroxidation.[22] Since lipid
peroxidation inhibits growth, there is an absence of growth restraint in
these cancer cells. Not only this, but tumor cells secrete a substance
which mobilizes (releases) unsaturated fats from storage, thus insuring
their supply until adipose (fat) tissue is depleted. [23] 

Consumption of unsaturated fats has been associated with both skin aging
and with the sensitivity of the skin to ultraviolet damage. According to
Black (1985) [24], ultraviolet light-induced skin cancer is mediated by
unsaturated fats and lipid peroxidation. 

Brain damage, lipid peroxidation and learning disabilities 

Let's talk about mice! I hate animal experiments, but I must tell you
about this one. Pregnant mice were fed either coconut oil or unsaturated
oil. The coconut oil mice had babies with normal brains and normal
intelligence. The unsaturated oil babies had smaller brains and inferior
intelligence. In another experiment, radioactively labeled soy oil was
given to nursing rats. This oil was massively incorporated into brain
cells, and caused visible structural changes in the cells. In 1980,
shortly after this study was published in Europe, the U.S. Department of
Agriculture (USDA) issued a recommendation against the use of soy oil in
infant formulas. Yet, most soymilk products still contain soybean oil.
More recently (Bell, et al. 1985), pregnant rats were given soy lecithin
with their food and the exposed offspring developed sensorimotor
defects. [25] Many other studies have shown that excessive unsaturated
oils interfere with learning and behavior. [26,27] 


Many studies, elsewhere reported have shown a connection between coconut
oil and weight loss versus unsaturated fats and obesity. Please refer to
the coconut oil article for more information. According to Peat, this
indicates the ability of coconut oil to stimulate thyroid function
versus the thyroid inhibiting effects of unsaturated oils. 

Is their hope after PUFA's? 

Yes! It is not the exact amount of unsaturated oils, which governs their
harm, but the amount of these compared to the amount of saturated fats.
Basically, the more saturated fats compared to the unsaturated oils, the
less harm done by the unsaturated oils. The healthiest saturated fats
are coconut oil and extra virgin olive oil. 

Some of the toxic effects of PUFA's can be reduced with antioxidants.
Antioxidants might include certain vitamins and minerals (vitamins A, E,
C, zinc, selenium) and antioxidant enzymes, such as catalase. In
addition, thyroxin (inactive form of thyroid hormone) is among the
structural antioxidants, and the known oxygen-sparing effects of
progesterone may make it appropriate to include among the structural

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8, 115, 1970. 2. Meade C.J. & J. Martin, et al. Adv. Lipid Res.,
127-165, 1978. 3. Borst, P., J. A. Loos, E. J. Christ, & E. C. Slater,
"Uncoupling action of long chain fatty acids," Biochem. Bioph. Acta. 62,
509- 18, 1962. 4. Lankin, I.Z, & E.A. Neifakh, Isv. Akad. Nauk. SSR,
Ser. Biol. , 2,263. 5. 6. Ikemoto, S., et al., High fat diet-induced
hyperglycemia, Proc. Nat. Acad. Sci., U.S.A. 92 (8), 3096-3099, 1995. 7.
8. Hashim, S., 1987 9. Selye, H., Sensitization by corn oil for the
production of cardiac necrosis, Amer. J. of Cardiology 23, 719-22, 1969.
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Dec. 1989, p. 637. 

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