No I can't.
It remains my "unproven suspicion". The definitive study
to determine the metabolic fate of dietary cholesterol has not yet
been done. It would involve putting a tag of some sort (most likely
a radiolabel) on dietary cholesterol and then seeing where it goes,
either via scan, biopsy, necropsy, or some friendlier method I haven't
thought of. My suspicion is that most of the plaque cholesterol
would turn out to be labeled.
also wonder about your statement "In spite of their high fat
content avocados and raw nuts lower cholesterol levels." Others,
like Mcdougall and Pinckney, say that these things must be avoided
if a vegan diet does not lower cholesterol enough.
I'm in substantial
disagreement with the low fat school of thought. I think it's animal
fat, refined plant fat, and hydrogenated fat that raises cholesterol
levels but don't see a problem with the natural plant fats of raw
nuts, seeds, and avocados. I append some supporting references.
that line, I posted this on Pincnkey's discussion group the other
day but have gotten no answers so far. Do you have any thoughts
on it? Don
has been stated earlier in this forum that a vegan lifestyle is
not enough for some people to reduce their cholesterol level to
a safe 150. Eliminating even "good" oils like olive oil,
nuts, avocado, etc. is recommended. One wonders why this should
be so. I would welcome comments on this hypothesis:
I do share Neal's
reservations about olive oil in spite of its 3000 year clear track
record. It is nevertheless 100% fat.
"good" oils are likely to cause the body to raise cholesterol
levels. One reason for this is that oils, whether vegetable or animal,
need bile to assist in their digestion. Bile is produced in the
liver, stored in the gall bladder, and released as needed into the
small intestine. Bile contains cholesterol. In fact, cholesterol
is a major component in about 80% of all gallstones. They develop
when bile contains an imbalance, with too much cholesterol and not
enough bile salts. So, consuming oils causes the liver to increase
its production of cholesterol. It becomes hyperactive in order to
deal with concentrated oils, an unnatural food. Some of this bile
cholesterol is then reabsorbed from the intestines and increases
the amount in the blood."
This is a reasonable
argument in support of the low fat position.
is said that the cholesterol in bile is of a different form from
that in the blood, and I wonder if this has any bearing on the situation.
there is no difference. Cholesterol consists of a 4 carbon-ring
nucleus with a precise arrangement of carbons attached to the top
of the #4 pentane ring. Since cholesterol is insoluble in water,
the only variable is the form of water soluble lipoprotein that
it uses for a carrier.
I can't give
a final answer on the idea that low fat consumption is the key to
good health. It may be, but before Nathan Pritikin came on the scene
it was traditional among quite healthy vegetarians to consume raw
nuts, seeds, and avocados in quantity and with no observable adverse
consequences. I personally go through a cup of seeds and nuts daily
and my cholesterol ranges from 120-158 mg%.
Effect of a
high-monounsaturated fat diet enriched with avocado in NIDDM patients.
Lerman-Garber I; Ichazo-Cerro S; Zamora-Gonzalez J; Cardoso-Saldana
G; Posadas-Romero C Department of Endocrinology, National Institute
of Cardiology Ignacio Chavez, Mexico City, Mexico. Diabetes Care
(UNITED STATES) Apr 1994, 17 (4) p311-5, ISSN 0149-5992 Journal
Code: EAG Languages: ENGLISH Document type: CLINICAL TRIAL; JOURNAL
ARTICLE; RANDOMIZED CONTROLLED TRIAL JOURNAL ANNOUNCEMENT: 9410
Subfile: INDEX MEDICUS OBJECTIVE--To assess the effects of two controlled
diets, one rich in oleic acid obtained from avocado and olive oil
and the other rich in complex carbohydrates, on fasting and postprandial
serum lipids and glycemic control in 12 women with NIDDM. RESEARCH
DESIGN AND METHODS--A randomized crossover study was designed. During
a 4-week baseline period, all patients received the isocaloric diets
recommended by the American Diabetes Association. After this period
the patients were randomly assigned to receive the two study diets
alternatively during two 4-week periods. One diet was high in monounsaturated
fatty acids (HMUFA) and the other was high in complex carbohydrates
(high-CHO). There also was a 4-week washout period in between the
two 4-week periods during which the patients followed the American
Diabetes Association's isocaloric diet. Blood samples were obtained
before and after each dietary period. RESULTS--Both diets had a
minor hypocholesterolemic effect with no major changes in high-density
lipoprotein cholesterol. The HMUFA diet was associated with a greater
decrement in plasma triglycerides (20 vs. 7% in the high-CHO diet).
Glycemic control was similar with both diets. CONCLUSIONS--Partial
replacement of complex digestible carbohydrates with monounsaturated
fatty acids (avocado as one of its main sources) in the diet of
patients with non-insulin-dependent diabetes mellitus improves the
lipid profile favorably, maintains an adequate glycemic control,
and offers a good management alternative.
avocado on the level of blood lipids in patients with phenotype
II and IV dyslipidemias] Efectos del aguacate sobre los niveles
de lipidos sericos en pacientes con dislipidemias fenotipo II y
IV. Carranza J; Alvizouri M; Alvarado MR; Chavez F; Gomez M; Herrera
JE Departemento de Investigacion Clinica y Biomedica, Hospital General
Dr. Miguel Silva, Morelia, Michoacan. Arch Inst Cardiol Mex (MEXICO)
Jul-Aug 1995, 65 (4) p342-8, ISSN 0020-3785 Journal Code: 7AA Languages:
SPANISH Summary Languages: ENGLISH Document type: CLINICAL TRIAL;
JOURNAL ARTICLE English Abstract JOURNAL ANNOUNCEMENT: 9605 Subfile:
INDEX MEDICUS To examine the effects of avocado on plasma lipid
concentrations a two-diet trial involving 8 phenotype IV and 8 phenotype
II dyslipidemia patients was carried out. A diet rich in monounsaturated
fatty acids (DRCA) using the avocado as their major source (30%
of the total calories were consumed as fat, 75% of the total fat
from the avocado), with restriction of saturated fat and less of
300 mg of cholesterol per day was evaluated. Patients also were
in a low-saturated fat diet without avocado (DRSA). The three daily
meals were eaten at our clinical unit. Diets were four weeks in
duration and they were assigned in a crossover design. In phenotype
II both DRCA and DRSA significantly reduced total cholesterol and
LDL-cholesterol levels. On phenotype IV DRCA produced a mild reduction
on triglyceride levels while DRSA increased them. On HDL-cholesterol
concentrations DRCA produced a significant increase in both phenotypes
while DRSA did it only in phenotype IV. Avocado is an excellent
source of monounsaturated fatty acids in diets designed to treat
hypercholesterolemia with some advantages over low-fat diets with
a greater amount of carbohydrates.
American Journal of Clinical Nutrition, Vol. 70, No. 3, 500S-503S,
September 1999 ©© 1999 American Society for Clinical Nutrition
vegetarian diets, ischemic heart disease risk, and all-cause mortality:
evidence from epidemiologic studies1,2 Joan Sabatéé
1 From the Departments of Nutrition and Epidemiology and Biostatistics,
School of Public Health, Loma Linda University, CA. Perhaps one
of the most unexpected and novel findings in nutritional epidemiology
in the past 5 y has been that nut consumption seems to protect against
ischemic heart disease (IHD). Frequency and quantity of nut consumption
have been documented to be higher in vegetarian than in nonvegetarian
populations. Nuts also constitute an important part of other plant-based
diets, such as Mediterranean and Asian diets. In a large, prospective
epidemiologic study of Seventh-day Adventists in California, we
found that frequency of nut consumption had a substantial and highly
significant inverse association with risk of myocardial infarction
and death from IHD. The Iowa Women's Health Study also documented
an association between nut consumption and decreased risk of IHD.
The protective effect of nuts on IHD has been found in men and women
and in the elderly. Importantly, nuts have similar associations
in both vegetarians and nonvegetarians. The protective effect of
nut consumption on IHD is not offset by increased mortality from
other causes. Moreover, frequency of nut consumption has been found
to be inversely related to all-cause mortality in several population
groups such as whites, blacks, and the elderly. Thus, nut consumption
may not only offer protection against IHD, but also increase longevity.
of Clinical Nutrition, Vol. 70, No. 3, 504S-511S, September 1999
©© 1999 American Society for Clinical Nutrition
Nuts and their bioactive constituents: effects on serum lipids and
other factors that affect disease risk1,2 Penny M Kris-Etherton,
Shaomei Yu-Poth, Joan Sabatéé, Hope E Ratcliffe, Guixiang
Zhao and Terry D Etherton 1 From the Graduate Program in Nutrition
and the Department of Dairy and Animal Science, The Pennsylvania
State University, University Park, and the Department of Nutrition,
School of Public Health, Loma Linda University, CA. 2 Address reprint
requests to PM Kris-Etherton, Nutrition Department, S-126 Henderson
Building, Pennsylvania State University, University Park, PA 16802.
INTRODUCTIONPREDICTIVE EQUATIONS FOR BLOOD... FAT, FATTY ACID, AND...
FEEDING STUDIES THAT USED... EVIDENCE OF NONFAT... BEYOND LIPIDS:
OTHER NUTRIENTS... PLANNING HEART-HEALTHY DIETS... SUMMARY AND CONCLUSIONS
have favorable fatty acid and nutrient profiles, there is growing
interest in evaluating their role in a heart-healthy diet. Nuts
are low in saturated fatty acids and high in monounsaturated and
polyunsaturated fatty acids. In addition, emerging evidence indicates
that there are other bioactive molecules in nuts that elicit cardioprotective
effects. These include plant protein, dietary fiber, micronutrients
such as copper and magnesium, plant sterols, and phytochemicals.
Few feeding studies have been conducted that have incorporated different
nuts into the test diets to determine the effects on plasma lipids
and lipoproteins. The total- and lipoprotein-cholesterol responses
to these diets are summarized in this article. In addition, the
actual cholesterol response was compared with the predicted response
derived from the most current predictive equations for blood cholesterol.
Results from this comparison showed that when subjects consumed
test diets including nuts, there was an 25% greater cholesterol-lowering
response than that predicted by the equations. These results suggest
that there are nonfatty acid constituents in nuts that
have additional cholesterol-lowering effects. Further studies are
needed to identify these constituents and establish their relative
cholesterol-lowering potency. 1999(suppl);70:504S11S.
received a degree in physics from the University of California Berkeley,
where he earned Phi Beta Kappa honors. He received his degree in
medicine from the University of California at San Francisco, and
received his postgraduate training at San Diego County Hospital.
He holds a Medical License in the State of Hawaii. He has been an
Emergency Department physican since 1963, and the Director of the
Kaiser Permanente Vegan Lifestyle Clinic on Oahu until his retirement
in 1998. Dr. Harris is the author of The Scientific Basis of Vegetarianism.
addition, he was the 1950 Big Ten Trampoline Champion, is an accomplished
hangglider and commercial pilot, and at age 70 became a skydiver
with 108 jumps to date. Dr. Harris has been vegetarian since 1950,
and vegan since 1963.