Bison - National Bison Association

Bison
An important food source
anti-carcinogen?
Wayne Askew, PhD. Division of Nutrition University of Utah
wayne.askew@health.utah.edu
Photo by Gary Crandall
Dancing Crane Studios
Purpose of this Presentation
• Does Bison meat contain a different array of
nutrients than feedlot beef?
• Do these nutrients impart health benefits?
• Focus on “Conjugated Linoleic Acid”
Does the consumption of this “unique” nutrient
impart some degree of human cardiovascular and
cancer “protection?
Is Bison Meat Anti-Carcinogenic?
-Is there any evidence that Bison meat
consumption is associated with a
reduction in cancer risk factors?
-The need for human clinical trials to
establish if Bison meat consumption has a
beneficial cancer prevention association
What Makes Bison Meat
“Different” From Cattle Meat?
• Red meat consumption ,specifically feedlot
beef, has been related epidemiologically to
several adverse health consequences:
-elevated blood lipids
-incidence of some types of cancer
• These relationships have not been reported
for Bison meat
• Bison meat consumption has been related to
a more “healthful” blood lipid profile
Cordain et al. Fatty acid analysis of wild ruminant tissues: Evolutionary Implications
for reducing diet related chronic disease. Eur J Clin Nutr 56:181-91, 2002
Why is Bison meat different from
beef cattle meat?
• Differences in nutrient composition (particularly
fat content)
• Partially genetic and partially due to differences in
feeding practices
• Do these factors really make a difference?
Scientific Studies Related to This Topic
•
According to scientists there is something “special” about
grass fed Bison meat…
•
Fatty acids in dietary materials consumed by ruminants
influence the fatty acid composition of their meat, affecting
flavor and health benefits for humans
•
High polyunsaturated fatty acid concentrations in ruminant
diets promote accumulation of desirable ω-3 fatty acids and
conjugated linoleic acid in muscle tissue
•
Increased grass intake results in an increase in the PUFA:SFA
ratio and the conjugated linoleic acid concentration in muscle.
The fatty acid composition of beef can be improved from a
human health perspective by inclusion of grass in the diet.
French, P. et al. J Anim Sci Nov;78:2849-55, 2000
Foster, J.G. et al. Am Forage And Grassland Council Conf Proc. 13:93, 500-50, 2004.
Izumi Y, et al. Proc Japanese Society for Rumen Metab and Physiol15, 43, 2002.
Rule, DC et al . J Anim Sci 80:1202-1211, 2002
Bison Meat Fat Content
Bison meat is leaner than beef or pork
Marchello, M.J., M. et al. Nutrient composition of raw and cooked Bison bison.
J. Food Comp. Anal. 2:177-185, 1989
Rule, DC et al Comparison of muscle fatty acid profiles and cholesterol concentrations of
bison, beef cattle, elk and chicken. J Anim Sci 80:1202-1211, 2002
Calories from Fat in a Typical
Serving of Bison, Beef or Pork
250
Fat (kcal/100g serving)
Beef and Pork typically have 45% more fat
200
Bison
150
Beef
100
Pork
50
0
Kcal/100g
USDA Handbook 8-5:8-10:8-13.8-17
Bison Meat Has a More
“Favorable” Fatty Acid Profile
Fatty Acid Composition of Bison Meat
Rule, DC et al Comparison of muscle fatty acid profiles and cholesterol
concentrations of bison, beef cattle, elk and chicken. J Anim Sci 80:1202-1211, 2002
Cordain et al. Fatty acid analysis of wild ruminant tissues: Evolutionary Implications
for reducing diet related chronic disease. Eur J Clin Nutr 56:181-91, 2002
Comparison of Lipid Content of
Semitendinosus Muscle* of
Bison and Beef
Conjugated Linoleic Acid
*Eye of the round
PUFA/SFA Ratio
Rule, DC et al Comparison of muscle fatty acid profiles and cholesterol
concentrations of bison,beef cattle, elk and chicken. J Anim Sci 80:1202-1211, 2002
Polyunsaturated Fat
vs
Saturated Fat
Unsaturated fat (PUFA)
considered less
“atherogenic”
(and more desirable)
than saturated fat
=
Saturated fat is
generally considered
more “atherogenic”
(and less desirable)
than unsaturated fat
P/S ratio
Comparison of Ratio of Polyunsaturated to
Saturated Fat in Bison and Beef Cattle Muscle*
A more “heart healthy” ratio
0.6
P/S ratio
0.5
0.4
P/S ratio:
Range Bison
Feedlot Bison
Feedlot Beef
The higher the P/S ratio
less “atherogenic” the fat,
(less adverse effect upon
blood cholesterol)
and the less the risk for
cardiovascular disease
0.3
0.2
0.1
0
A less “heart healthy” ratio
P/S Ratio
*Semitendinosis muscle
(eye of the round)
Rule, DC et al Comparison of muscle fatty acid profiles and cholesterol concentrations
of bison,beef cattle, elk and chicken. J Anim Sci 80:1202-1211, 2002
Let’s Focus on One Particular
Unsaturated Fatty Acid
Conjugated Linoleic Acid
(CLA)
Effect of double bond on Fatty Acid Conformation
trans 10, cis 12 CLA
cis 9, trans 11 CLA
linoleic acid (cis 9, cis 12)
Why the Interest in CLA?
CLA is believed to be a
“healthy” fat
Much of the recent research on CLA
has focused upon its potential anti-carcinogenic properties
Belury, M.A.. Inhibition of Carcinogenesis by Conjugated Linoleic Acid
Potential Mechanisms of Action. J. Nutr 132:2995-98, 2002
Reported Health Benefits of
Conjugated Linoleic Acid
•
•
•
•
Increases metabolic rate
Decreases abdominal fat
Enhances muscle growth
Lowers blood cholesterol and
triglycerides
• Lowers insulin resistance
• Enhances immune system function
• Possibly anti-carcinogenic
Bellury M.A. Dietary Conjugated Linoleic Acid in Health:
Physiological Effects and Mechanisms of Action Ann Rev Nutr 22:505-31, 2002
Total Conjugated Linoleic Acid, wt %
Comparison of Bison and Beef Cattle
Muscle (semitendinosis)
Conjugated Linoleic Acid Composition
Interpretation of CLA Content:
0.45
0.4
Range Bison
Feedlot Bison
Feedlot Beef
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
CLA is believed to be a
“beneficial” fatty acid, with
anti-inflammatory and
possibly anti-carcinogenic
properties
Bison meat
has ~14% more CLA
than feedlot fed beef
CLA
*Semitendinosis muscle
(eye of the round)
Rule, DC et al Comparison of muscle fatty acid profiles and cholesterol concentrations
of bison,beef cattle, elk and chicken. J Anim Sci 80:1202-1211, 2002
Where does Conjugated Linoleic
Acid (CLA) come from?
• Biological synthesis of CLA occurs through the
microbial isomerization of dietary linoleic and
linolenic acid in the digestive tracts of ruminant
animals
• Ruminant species and their products are rich
dietary sources of CLA, particularly if grass or hay
fed
• The major dietary sources of CLA for humans are
beef and dairy products
Tanaka, K. Occurrence of Conjugated Linoleic Acid in Ruminant Products
and its Physiological Functions. Anim Sci J 76:291-303, 2005
Major Dietary Food Sources of
Conjugated Linoleic Acid for Humans
Beef
32%
Dairy
60%
K. L. Ritzenthaler et al. Estimation of Conjugated Linoleic Acid Intake…
J Nutrition. 2001;131:1548-155
Beef
Pork
Poultry
Dairy
Other
Health implications of CLA
Reduction in cell tumor proliferation?
• CLA can delay or reduce the onset of chemically
induced tumors in various sites of rats and mice,
including skin, mammary glands, and stomach
• How does CLA do this?
What “causes” cancer?
Complex etiology, but
Inflammation
is believed to play a “key”
role
Cancer
and
Chronic Inflammation:
What’s the connection?
Theory:
Chronic irritation elicits an
inflammatory response which
may facilitate the setting in
which cells grow abnormally
Cancer and Inflammation (CIBA Foundation Symposia Series) 2004
by Jamie A. Goode, SYMPOSIUM ON CANCER AND INFLAMMATION,
Inflammation
Recovery
Chronic Inflammation and Cancer
Repeated insults
lead to chronic tissue
damage and
chronic inflammation
which leads to
an imbalance of
pro and anti-inflammatory
cytokines which may
increase the risk of cancer
Cell death
Cell death
Injury
Cell death
Cell death
Disease
l death
Genetic
mutations
Cell death
Toxins
Cell death
Cell death
The Cancer “Puzzle”
Cell death
CLA
CLA
Cell death
CLA
Cell death
l death
Injury
Disease
CLA
Genetic
mutations
Cell death
Cell death
CLA
Toxins
CLA
CLA
CLA
Cell death
Cell death
Much of the anti-carcinogenic research on
CLA has been done with a mouse model in
which cancer has been introduced
In Normal Humans What can be measured?
Biomarkers Related to Cancer Risk
Chronic inflammation is associated with
processes that contribute to the onset or
progression of cancer
Circulating levels of inflammatory biomarkers:
-C-reactive protein (CRP), Tumor necrosis factor-α
(TNF-α), Interleukin-6 (IL-6)
Urinary excretion of damaged DNA bases:
-Oxidized DNA bases (8-OHdG)
SUMMARY
Bison Meat, CLA and Health
Because such small amounts of CLA (0.5% of
diet) have been shown to alter the expression of
genes and impact conditions such as
carcinogenesis, obesity, diabetes, and
atherosclerosis in experimental animals,
it is possible that small amounts consumed in
food over a prolonged period of time may exert
similar beneficial effects in human beings. This
is conjecture at this point until human clinical
trails have been conducted.
Human Clinical Trials are Needed
to Determine the
Health Benefits of Bison meat