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Department of Nutrition, Harvard School
of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.
CONTEXT: Nuts are high in unsaturated
(polyunsaturated and monounsaturated) fat and other nutrients
that may improve glucose and insulin homeostasis. OBJECTIVE:
To examine prospectively the relationship between nut consumption
and risk of type 2 diabetes. DESIGN, SETTING, AND PARTICIPANTS:
Prospective cohort study of 83 818 women from 11 states in
the Nurses' Health Study. The women were aged 34 to 59 years,
had no history of diabetes, cardiovascular disease, or cancer,
completed a validated dietary questionnaire at baseline in
1980, and were followed up for 16 years. MAIN OUTCOME MEASURE:
Incident cases of type 2 diabetes. RESULTS: We documented
3206 new cases of type 2 diabetes. Nut consumption was inversely
associated with risk of type 2 diabetes after adjustment for
age, body mass index (BMI), family history of diabetes, physical
activity, smoking, alcohol use, and total energy intake. The
multivariate relative risks (RRs) across categories of nut
consumption (never/almost never, <once/week, 1-4 times/week,
and > or =5 times/week) for a 28-g (1 oz) serving size
were 1.0, 0.92 (95% confidence interval [CI], 0.85-1.00),
0.84 (0.95% CI, 0.76-0.93), and 0.73 (95% CI, 0.60-0.89) (P
for trend <.001). Further adjustment for intakes of dietary
fats, cereal fiber, and other dietary factors did not appreciably
change the results. The inverse association persisted within
strata defined by levels of BMI, smoking, alcohol use, and
other diabetes risk factors. Consumption of peanut butter
was also inversely associated with type 2 diabetes. The multivariate
RR was 0.79 (95% CI, 0.68-0.91; P for trend <.001) in women
consuming peanut butter 5 times or more a week (equivalent
to > or =140 g [5 oz] of peanuts/week) compared with those
who never/almost never ate peanut butter. CONCLUSIONS: Our
findings suggest potential benefits of higher nut and peanut
butter consumption in lowering risk of type 2 diabetes in
women. To avoid increasing caloric intake, regular nut consumption
can be recommended as a replacement for consumption of refined
grain products or red or processed meats.
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Department of Clinical Nutrition, University
of Goteborg, Sahlgrenska Hospital, Gothenburg, Sweden.
Butter was replaced by olive oil
in a controlled 100 g fat diet in order to study the effect
of saturated fats (SAFA) versus monounsaturated fats (MUFA)
on small-bowel sterol excretion in eleven healthy ileostomates.
Bile acids and neutral sterols were measured by gas-liquid
chromatography. Net cholesterol excretion (excretion minus
intake) was 84 +/- 25 mg/24 h (mean +/- SE) on the SAFA
diet and increased to 218 +/- 32 mg/24 h on the MUFA diet
(P less than 0.01). The bile acid excretion tended to be
somewhat lower on the MUFA diet, but this was significant
only for chenodeoxycholic acid. Net sterol excretion (the
sum of excretion of net cholesterol and bile acids) was
significantly lower on the SAFA diet than on the MUFA diet
(443 +/- 60 and 529 +/- 58 mg/24 h, respectively). The immediately
increased excretion of cholesterol from the small bowel
could thus explain the serum cholesterol-lowering effect
of a change from a SAFA-rich to a MUFA-rich diet, though
the mechanism for this change is still unclear.
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The effect of a fat-modified diet
with 1100 kcal (4600 kJ) on the reduction of body weight
and body fat was studied. A low-carbohydrate, high-fat diet
with predominant animal fat (diet T) was compared with a
low-carbohydrate, high-fat diet with predominant vegetable
fat (diet P). Diet T was composed of 52.1% of the energy
as fat, 20.7% as protein and 27.2% as carbohydrates. Diet
P was composed of 54.1% of the energy as fat, 18.9% as protein
and 27.0% as carbohydrates. More than two-thirds of the
fat in diet T was butter, in diet P margarine. The study
was carried out with 30 subjects (8 men) over two 21-day
periods. With diet T, men had a mean weight loss of 7.1
kg = 338 g/d, of which 3.2 kg = 152 g/d were proved to be
body fat, while women had a mean weight loss of 4.4 kg =
210 g/d, of which 2.3 kg = 110 g/d were proved to be body
fat. With diet P, men had a mean weight loss of 7,6 kg =
362 g/d, of which were 3.9 kg = 186 g/d body fat, while
women lost 3.8 kg = 181 g/d of body weight on average, of
which were 2.0 kg = 95 g/d body fat. An improvement of blood
pressure was also found. Significant differences of the
reduction of body weight and body fat between the diet with
mostly animal fat and the diet with mostly vegetable fat
were not found.
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Department of Human Nutrition, Wageningen
Agricultural University, The Netherlands.
Intake of trans fatty acids unfavorably
affects blood lipoproteins. As margarines are a major source
of trans, claims for the advantages of margarines over butter
need to be scrutinized. Here we review dietary trials that
directly compared the effects of butter and margarine on
blood lipids. We identified 20 studies in which subjects
had stable body weights, and margarine and butter were exchanged
in the diet at constant energy and fat intake. We calculated
the changes in average blood lipid levels between study
diets (49 comparisons) as a function of the percentage of
calories as margarine substituted for butter. Replacing
10% of calories from butter by hard high-trans stick margarines
lowered total serum cholesterol by 0.19, LDL by 0.11, and
HDL by 0.02 mmol/l, and did not affect the total/HDL cholesterol
ratio. Soft low-trans tub margarines decreased total cholesterol
by 0.25 and LDL by 0.20 mmol/l, did not affect HDL, and
decreased the total/HDL cholesterol ratio by 0.20. Based
on the total/HDL cholesterol ratio, replacement of 30 g
of butter per day by soft tub margarines would theoretically
predict a reduction in coronary heart disease risk of 10%,
while replacement of butter by hard, high-trans margarines
would have no effect. Replacing butter by low-trans soft
margarines favorably affects the blood lipoprotein profile
and may reduce the predicted risk of coronary heart disease,
but high-trans hard margarines probably confer no benefit
over butter.
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Department of Social and Preventive Medicine,
School of Medicine, State University of New York, Buffalo
14214-299.
The cross-sectional association between
consumption of various fats (eg, butter, olive oil, and
vegetable oil) and risk factors for coronary heart disease
was analyzed in a sample of 4903 Italian men and women 20
to 59 years of age. The intake of fats was ascertained by
an interviewer-administered questionnaire. Increased consumption
of butter was associated with significantly higher blood
pressure and serum cholesterol and glucose levels for men;
in women only the association with glucose reached statistical
significance. In both sexes consumption of olive oil and
vegetable oil was inversely associated with serum cholesterol
and glucose levels and systolic blood pressure. These findings
were adjusted for confounding effects of other risk factors
for cardiovascular disease. These cross-sectional findings
from a large population sample suggest that consumption
of butter may detrimentally affect coronary risk factors,
while polyunsaturated and monounsaturated fats may be associated
with a lower coronary risk profile.
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Department of Cell Biology, Physiology
and Immunology, Medical Physiology Unit, Medical School, Universitat
Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Effects of a high virgin olive oil
diet on the promotion stage of dimethylbenz(alpha)anthracene-induced
mammary carcinogenesis in rats were investigated in comparison
with those of a high corn oil diet. Animals were randomly
placed into 4 groups: control, fed a normolipidic control
diet (3% corn oil); M, fed a high corn oil diet (20%); O,
fed a high olive oil diet (3% corn oil plus 17% olive oil);
and MO, fed the high olive oil diet after 33 days of high
corn oil diet. Whereas the high corn oil diet clearly stimulated
the mammary carcinogenesis, reducing the latency time and
increasing the tumor incidence, multiplicity and volume,
the high olive oil diet led to a lower tumor incidence than
in the former group, a latency time similar to that of the
control and lower tumor multiplicity and volume even than
in the control group. Moreover, the histopathological features
of the adenocarcinomas in olive oil groups were compatible
with a greater degree of differentiation. These data suggest
that the high virgin olive oil diet would have acted as
a negative modulator of the experimental mammary carcinogenesis
conferring to the tumors a more benign clinical behavior
and a lower histopathological malignancy in comparison with
the control and high corn oil diets.
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Institute of Nutritional Sciences,
University of Vienna, Austria.
BACKGROUND: The effects of monounsaturated
fatty acids (MUFA) rich diets compared to those that are
rich in polyunsaturated fatty acids (PUFA) as well as the
effects of an intake of single oils compared to oil mixtures
are controversially discussed and results are contradictory.
AIM OF THIS STUDY: To evaluate the effects of a plant oil-mixture
(olive/sunflower oil; saturated/monounsaturated/polyunsaturated
(S/M/P) = 14:69:17) high in oleic acid but also showing
a moderate content of polyunsaturated fatty acids (PUFA)
in comparison with a single, PUFA rich corn oil (S/M/P =
13:33:54) used in a normal, balanced diet on human plasma
and lipoprotein metabolism. METHODS: The double-blind designed
study comprised 28 healthy, non-smoking young men aged between
19 and 31 years. After two weeks of adjustment (mixed, balanced
diet: 11.6 MJ average, average fat intake approximately
105 g/d), the design included a two week test period in
which a diet with 80 g corn oil/d vs a mixture of 68 g olive-
and 12 g sunflower oil/d (total 80 g) as the main fat source
was given, followed by a crossover after two weeks. Compliance
and ingestion of diets were monitored by assessing the fatty
acid pattern in LDL and by determination of alpha- and gamma-tocopherol
in plasma and LDL. Results Diets were well incorporated
due to the significant changes in plasma- and LDL-tocopherol
levels and the significant different average ratio of oleic
acid to linoleic acid in LDL. The PUFA-rich corn oil diet
was able to reduce low density lipoprotein (LDL) cholesterol
from adjustment to T2 significantly (p < 0.01), which
was also confirmed by a trend after cross over (p=0.15).
Total cholesterol (only after cross over at T3), total triglycerides
(TG) and very low density lipoprotein (VLDL)-TG were significantly
lower at T2 after the corn oil diet than after the mixed
oil diet. Total high density lipoproteins (HDL) and HDL
cholesterol remained unchanged by both diets. CONCLUSIONS:
The results show that during the intervention of two weeks
for each diet and the following cross over the corn oil
diet had more influence on lipoprotein metabolism than the
MUFA-rich diet. The hypocholesteremic effect of the PUFA-rich
diet must also be connected with the high amount of unsaponifiable
substances, mainly phytosterols in the corn oil.
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Food and Nutrition Science Consulting,
Fort Collins, CO 80524.
This review of corn oil provides
a scientific assessment of the current knowledge of its
contribution to the American diet. Refined corn oil is composed
of 99% triacylglycerols with polyunsaturated fatty acid
(PUFA) 59%, monounsaturated fatty acid 24%, and saturated
fatty acid (SFA) 13%. The PUFA is linoleic acid (C18:2n-6)
primarily, with a small amount of linolenic acid (C18:3n-3)
giving a n-6/n-3 ratio of 83. Corn oil contains a significant
amount of ubiquinone and high amounts of alpha- and gamma-tocopherols
(vitamin E) that protect it from oxidative rancidity. It
has good sensory qualities for use as a salad and cooking
oil. Corn oil is highly digestible and provides energy and
essential fatty acids (EFA). Linoleic acid is a dietary
essential that is necessary for integrity of the skin, cell
membranes, the immune system, and for synthesis of icosanoids.
Icosanoids are necessary for reproductive, cardiovascular,
renal, and gastrointestinal functions and resistance to
disease. Corn oil is a highly effective food oil for lowering
serum cholesterol. Because of its low content of SFAs which
raises cholesterol and its high content of PUFAs which lowers
cholesterol, consumption of corn oil can replace SFAs with
PUFAs, and the combination is more effective in lowering
cholesterol than simple reduction of SFA. PUFA primarily
lowers low-density-lipoprotein cholesterol (LDL-C) which
is atherogenic. Research shows that PUFA has little effect
on high-density-lipoprotein cholesterol (HDL-C) which is
protective against atherosclerosis. PUFA generally improves
the ratio of LDL-C to HDL-C. Studies in animals show that
PUFA is required for the growth of cancers; the amount required
is considered to be greater than that which satisfies the
EFA requirement of the host. At this time there is no indication
from epidemiological studies that PUFA intake is associated
with increased risk of breast or colon cancer, which have
been suggested to be promoted by high-fat diets in humans.
Recommendations for minimum PUFA intake to prevent gross
EFA deficiency are about 3% of energy (en%). Recommendations
for prevention of heart disease are 8-10 en%. Consumption
of PUFA in the United States is 5-7 en%. The use of corn
oil to contribute to a PUFA intake of 10 en% in the diet
would be beneficial to heart health. No single source of
salad or cooking oil provides an optimum fatty acid (FA)
composition. Many questions remain to be answered about
the relation of FA composition of the diet to various physiological
functions and disease processes.
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The Hebrew University of Jerusalem, Faculty
of Agricultural, Food and Environmental Quality Sciences,
Rehovot, Israel.
Olive oil is an integral ingredient
of the Mediterranean diet and accumulating evidence suggests
that it may have health benefits that include reduction
of risk factors of coronary heart disease, prevention of
several varieties of cancers, and modification of immune
and inflammatory responses. Olive oil appears to be an example
of a functional food, with varied components that may contribute
to its overall therapeutic characteristics. Olive oil is
known for its high levels of monounsaturated fatty acids
and is also a good source of phytochemicals including polyphenolic
compounds, squalene, and alpha-tocopherol.
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Istituto di Ricerche Farmacologiche Mario
Negri, Milan, Italy.
OBJECTIVE: This study investigates
the potential role of olive oil and other added fats used
for seasoning or cooking on ovarian carcinogenesis. METHODS:
We analyzed data from a multicentre case-control study conducted
between 1992 and 1999 in Italy, including a total of 1031
incident with a first diagnosis, histologically confirmed
epithelial ovarian cancer cases and 2,411 hospital controls
with acute, non-malignant and non-gynecological conditions.
The subjects' usual diet was investigated through a validated
food-frequency questionnaire, including specific questions
aimed at assessing added fat intake patterns. RESULTS: After
allowance for study centre, year at interview, age, education,
parity, oral contraceptive use, and total energy intake,
a reduced risk of ovarian cancer was observed for high intake
of olive oil (odds ratio (OR) = 0.68, 95% confidence interval
(CI) 0.50-0.93 for the highest quintile of intake, compared
to the lowest one) and for a group of specific seed oils
(i.e. sunflower, maize, peanut, and soya) (OR = 0.59, 95%
CI 0.46-0.76). No significant associations were observed
for mixed seed oils, butter, and margarine. CONCLUSIONS:
The present study suggests a favorable effect of olive oil
and other vegetable oils on ovarian cancer in this Italian
population.
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Division of Toxicology and Cancer Risk
Factors, German Cancer Research Center, Heidelberg.
In the Mediterranean basin, olive
oil, along with fruits, vegetables, and fish, is an important
constituent of the diet, and is considered a major factor
in preserving a healthy and relatively disease-free population.
Epidemiological data show that the Mediterranean diet has
significant protective effects against cancer and coronary
heart disease. We present evidence that it is the unique
profile of the phenolic fraction, along with high intakes
of squalene and the monounsaturated fatty acid, oleic acid,
which confer its health-promoting properties. The major
phenolic compounds identified and quantified in olive oil
belong to three different classes: simple phenols (hydroxytyrosol,
tyrosol); secoiridoids (oleuropein, the aglycone of ligstroside,
and their respective decarboxylated dialdehyde derivatives);
and the lignans [(+)-1-acetoxypinoresinol and pinoresinol].
All three classes have potent antioxidant properties. High
consumption of extra-virgin olive oils, which are particularly
rich in these phenolic antioxidants (as well as squalene
and oleic acid), should afford considerable protection against
cancer (colon, breast, skin), coronary heart disease, and
ageing by inhibiting oxidative stress.
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Unitat de Lipids i Epidemiologia Cardiovascular,
Institut Municipal d'Investigacio Medica (IMIM), Carrer Dr.
Aiguader, 80, 08003 Barcelona, Espagne.
longside the French paradox, the
REGICOR Study (Girona, Spain) has shown another paradox
in the Mediterranean area: a high prevalence of cardiovascular
risk factors with low incidence of myocardial infarction
in the population of Girona, Spain. The antioxidant effects
associated with olive oil consumption could explain part
of this 'Mediterranean Paradox'. Virgin olive oils processed
by two centrifugation phases and with low fruit ripeness
have the highest levels of antioxidant content. The total
content of phenolic compounds (PC) from virgin olive oil
could delay LDL oxidation. The content and nature of olive
oil PC have a high influence in the antioxidant capacity
of an olive oil. PC from diet could bind human LDL in non-supplemented
volunteers. PC from virgin olive oil could bind LDL and
tyrosol is bioavailable in humans from ingestion of virgin
olive oil in its natural form.
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Institute of Clinical Chemistry and Laboratory
Medicine, University of Munster, Germany.
Various studies have already shown
that the fatty acid composition of dietary fat has different
effects on hemostasis and platelet function. However, knowledge
on this topic is incomplete. In the present study, fifty-eight
healthy students received either a 4-week rapeseed oil [high
content of monounsaturated fatty acids (MUFA) and high n-3/n-6
PUFA ratio], an olive oil (high content of MUFA, low n-3/n-6
PUFA ratio) or a sunflower oil (low content of MUFA, low
n-3/n-6 PUFA ratio) diet. In each group, effects on hemostatic
parameters were compared with a wash-in diet rich in saturated
fatty acids with respect to intermediate-time effects on
the hemostatic system and platelet function. With the olive
oil diet, a reduction of coagulation factors VIIc, XIIc,
XIIa, and Xc was found, whereas sunflower oil led to lower
values of coagulation factors XIIc, XIIa, and IXc. In all
study groups levels of plasmin-alpha2-antiplasmin were lower
in week 4 than at baseline. Lower fibrinogen binding on
platelets was found after the sunflower oil diet, whereas
expression of CD62 and spontaneous platelet aggregation
were slightly higher after the olive oil diet. However,
given the major differences in the fatty acid compositions
of the diets, the differences between the groups with respect
to hemostasis tended to be small. Therefore, the clinical
significance of the present findings remains to be evaluated.
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Dipartimento di Scienze Biomediche, Sezione
di Microbiologia e Clinica, Universita degli studi di Sassari,
Viale S. Pietro 43/B, 07100 Sassari, Italy.
AIMS: To evaluate the antimicrobial
effect of the ozonized sunflower oil (Oleozon) on different
bacterial species isolated from different sites. METHODS AND
RESULTS: The effect of Oleozon on Mycobacteria, staphylococci,
streptococci, enterococci, Pseudomonas and Escherichia coli
was tested. The sunflower oil was ozonized at the Centro de
Investigaciones del Ozone (CENIC, Havana, Cuba) by an ozone
generator. MICs were determined by the agar dilution method.
For Mycobacteria, the MIC of Oleozon was determined on solid
medium by a microdrop agar proportion test. Oleozon showed
antimicrobial activity against all strains analysed, with
an MIC ranging from 1.18 to 9.5 mg ml-1. CONCLUSION: Oleozon
showed a valuable antimicrobial activity against all micro-organisms
tested. Results suggest that Mycobacteria are more susceptible
to Oleozon than the other bacteria tested. SIGNIFICANCE AND
IMPACT OF THE STUDY: The wide availability of sunflower oil
makes Oleozon a competitive antimicrobial agent. These results
should prompt the setting up of some clinical trials to compare
Oleozon with other antimicrobial agents.
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Department of Nutrition, University of
Helsinki, Finland.
In this highly controlled trial,
26 normolipidemic men (average age 28 years, range 18 to
60) were fed a baseline diet high in milk fat (MF) (fat
36% of energy, saturates 19%, monounsaturates 11%, polyunsaturates
4%), followed by a diet high in sunflower oil (SO) (fat
38% of energy, saturates 13%, monounsaturates 10%, polyunsaturates
13%) and another diet high in low erucic-acid rapeseed oil
(RO) (fat 38% of energy, saturates 12%, monounsaturates
16%, polyunsaturates 8%). All diets were mixed natural diets
with the same cholesterol contents. The baseline milk fat
diet was given for 14 days and the oil diets for 24 days
in a blind cross-over design. The platelet in vitro aggregation
(slope %/min) induced by 1, 2 and 3 microM ADP and collagen
(25 micrograms/ml PRP) was highly significantly (p less
than 0.001) increased after both oil diets when compared
with the results from the milk fat diet. The aggregation
pattern determined by threshold collagen concentration confirmed
increased collagen sensitivity of the platelets after the
rapeseed oil diet (p less than 0.001). The enhancement of
platelet aggregation was associated with increased in vitro
platelet thromboxane production after the oil diets vs.
the milk fat diet (p less than 0.05 after the sunflower
oil diet and p less than 0.001 after the rapeseed oil diet).
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Department of Physiological and Biological
Sciences, Maharishi International University, Fairfield, Iowa
52556.
Sesame contains large quantities of
the essential polyunsaturated fatty acid (PUFA), linoleic
acid, in the form triglycerides. The antineoplastic properties
of many PUFAs such as linoleic acid and their metabolites
are known. We tested the hypothesis that natural vegetable
oils, such as sesame oil and its component linoleic acid,
when added to human colon adenocarcinoma cells growing in
tissue culture would inhibit their growth and that normal
colon cells would not be similarly affected. Three human colon
cancer cell lines and one normal human colon cell line were
exposed to the following: (1) pure linoleic acid; (2) lipase-digested
sesame oil; (3) undigested sesame oil; (4) five additional
common vegetable oils; (5) mineral oil. Linoleic acid inhibited
the in vitro growth of all three malignant human colon adenocarcinoma
cell lines. The normal colon cell line showed dramatically
less inhibition of growth. Lipase-digested sesame oil (LDSO)
and undigested sesame oil (UDSO) produced greater inhibition
of growth of all three malignant colon cell lines than of
the normal colon cells. Five other common vegetable oils containing
various amounts of PUFAs such as corn, soybean, safflower,
olive and coconut oils, all in their lipase-digested form,
were found to dramatically inhibit the growth of the HT-29
malignant human colon cell line. Undigested olive and safflower
oils also inhibited the HT-29 cells although not as markedly
as the lipase-digested oils. Mineral oil did not inhibit the
growth of HT-29 cells. Both lauric and palmitic acid, which
are saturated fatty acids found in abundance in coconut oil
inhibits the HT-29 cells more strongly than linoleic acid,
while oleic acid did not inhibit. We conclude that many vegetable
oils including sesame contain in vitro antineoplastic properties
and that this finding warrants further investigation both
in vitro and in vivo to assess their possible chemotherapeutic
potential.
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Department of Food Science, RMIT University,
Melbourne, VIC, Australia.
Scientific evidence is accumulating
that meat itself is not a risk factor for Western lifestyle
diseases such as cardiovascular disease, but rather the
risk stems from the excessive fat and particularly saturated
fat associated with the meat of modern domesticated animals.
In our own studies, we have shown evidence that diets high
in lean red meat can actually lower plasma cholesterol,
contribute significantly to tissue omega-3 fatty acid and
provide a good source of iron, zinc and vitamin B12. A study
of human and pre-human diet history shows that for a period
of at least 2 million years the human ancestral line had
been consuming increasing quantities of meat. During that
time, evolutionary selection was in action, adapting our
genetic make up and hence our physiological features to
a diet high in lean meat. This meat was wild game meat,
low in total and saturated fat and relatively rich in polyunsaturated
fatty acids (PUFA). The evidence presented in this review
looks at various lines of study which indicate the reliance
on meat intake as a major energy source by pre-agricultural
humans. The distinct fields briefly reviewed include: fossil
isotope studies, human gut morphology, human encephalisation
and energy requirements, optimal foraging theory, insulin
resistance and studies on hunter-gatherer societies. In
conclusion, lean meat is a healthy and beneficial component
of any well-balanced diet as long as it is fat trimmed and
consumed as part of a varied diet.
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