Transcript Trans Fat

FSNE Nutrition Workshop
Fats
Lisa Lachenmayr
June 2006
Dietary Guidelines Key Recommendations
Adults:
20-35% of calories
Children 4-18 years old: 25-35% of calories
Children 2-3 years old: 30-35% of calories
Less than 10% of calories from saturated fatty acids
Less than 300 mg/day of cholesterol
Keep trans fatty acids as low as possible
Fats in Foods
Phospholipids
Sterols
Triglycerides
– Common names: Fats and Oils
– 95% of the fat in food
– 9 kcal/gram
– Glycerol backbone + 3 Fatty Acids
Different Types of Fatty Acids
Polyunsaturated
– Essential
– Omega-6
– Omega-3
Monounsaturated
Saturated
Trans
Fatty Acids in Foods
Mixed Triglycerides
– Length (Number of carbons in a chain)
– Degree of saturation
Food contains a mixture of fatty acids
Foods classified based on predominant fatty acid
Polyunsaturated Fatty Acids
Dietary Guidelines
– “Keep total fat intake between 20-35% of calories, with most coming
from sources of polyunsaturated and monounsaturated fatty acids…”
Primarily found in vegetable oils
Decreased risk of CHD associated with replacing
dietary saturated fats with polyunsaturated fats while
maintaining a low intake of trans fatty acids
Good source of essential fatty acids and Vitamin E
Polyunsaturated Fatty Acids
Omega-6
Sources: Vegetable oils such as soybean, corn and
safflower
High in Western Diet
Essential Omega-6 FA: Linoleic Acid
Polyunsaturated Fatty Acids
Omega-3
Alpha linolenic
– Plant source such as soybean and canola oil, walnuts and flaxseed
– Essential Omega-3 FA
DHA and EPA
– Animal sources such as fish and shellfish
– Especially high in fatty fish including salmon, lake trout, tuna and
herring
Dietary Guidelines – EPA and DHA
General Population:
– Limited evidence suggestions consumption
of FA in fish and decreased mortality from
CVD
Previous Cardiac Event:
– Evidence suggests consuming 2 servings of
fish per week decreases risk of heart
disease
– EPA and DHA decreases risk of mortality
from CVD
Fish Consumption Concerns
Mercury
– Discussed in Dietary Guidelines
– Heavy metal toxin found in varying levels in nearly all fish and
shellfish
– Not a health concern for general population
– EPA and FDA recommend following special consumption guidelines
for certain populations:
- Woman of childbearing age who may become pregnant
- Pregnant women
- Nursing mothers
- Young children
Mercury in Fish – Guidelines for Special Populations
High Levels – Avoid
Low Levels - Consume
Shark
Shrimp
Swordfish
Canned Light Tuna*
King Mackerel
Salmon
Tilefish
Pollock
Locally Caught Fish
Catfish
Fish sticks and processed fish
- Check local advisories and avoid if sandwiches
recommended
- Consume only 6 ounces per week
*Albacore (white) tuna has more mercury than canned light tuna. You
may eat up to 6 ounces of albacore tuna per week (one average meal)
and 6 ounces of tuna steaks per week.
Salmon – Farmed vs. Wild
Farm Raised
– Higher levels of contaminants (Including PCBs and dioxins)
– Where fish is farmed matters
– Recommendations of 1-2 meals (8 ounces) per month based on EPA
guidelines
Wild
– Lower levels of contaminants
– Recommendations of up to 8 meals per month
Labels
– “Fresh” – Does not mean wild-caught
– “Atlantic” – Almost always farmed
American Heart Association – DHA and EPA
Decrease risk of arrhythmias
Decreased blood clots
Decrease triglyceride levels
Decrease growth of plaque
Lower blood pressure (slightly)
AHA Recommendations – DHA and EPA
Population
Recommendation
Without CHD
-Eat a variety of fish (preferably fatty) at least 2
times per week
- Include oils and foods rich in alpha-linolenic*
With CHD
-Eat 1g of EPA + DHA per day preferably from
fatty fish
- Consult doctor about supplements
Need to lower triglycerides -Eat 2-4 grams of EPA+ DHA per day via
supplements (consult doctor)
- High intakes of EPA and DHA could cause
excessive bleeding
- High-quality omega-3 fatty acid supplements
*Alpha-linolenic acid can be converted to DHA and EPA in the body. This
conversion is modest and controversial. Alpha-linolenic acid is found in
flaxseed and flaxseed oil, canola and soybean oils and walnuts.
EPA and DHA Health Claim
FDA Allowed Health Claim (2004)
– Supportive but not conclusive research shows that
consumption of EPA and DHA omega-3 fatty acids may reduce
the risk of coronary heart disease. One serving of [name of
food] provides [x] grams of EPA and DHA omega-3 fatty acids.
[See nutrition information for total fat, saturated fat and
cholesterol content.]
DHA - Infants
Visual and cognitive development in infants
Found in breast milk
– Higher if a mother's diet is high in fish
FDA approved addition of DHA and Arachidonic acid
(ARA) to infant formula in 2002
– FDA indicating “safe”
Limited research on benefit of addition of DHA and
ARA
Monounsaturated Fatty Acids
Dietary Guidelines
– “Keep total fat intake between 20-35% of calories, with most coming
from sources of polyunsaturated and monounsaturated fatty acids…”
Primarily found in canola and olive oils, some nuts
and avocados
Decreased risk of CHD associated with replacing
dietary saturated fats with monounsaturated fats
while maintaining a low intake of trans fatty acids
Decreases Total and LDL Cholesterol
Olive Oil Health Claim
FDA Allowed Health Claim (2004)
– Limited and not conclusive scientific evidence suggests that
eating about 2 tablespoons (23 grams) of olive oil daily may
reduce the risk of coronary heart disease due to the
monounsaturated fat in olive oil. To achieve this possible
benefit, olive oil is to replace a similar amount of saturated fat
and not increase the total number of calories you eat in a day.
One serving of this product [Name of food] contains [x] grams
of olive oil.
Saturated Fatty Acids
Dietary Guidelines
– Consume less than 10% of calories from saturated fatty acids…
Primarily found in animal products and tropical oils
Increases risk of CHD
– Increases LDL cholesterol
– Number one dietary link to high blood cholesterol
– Decreasing consumption appears to significantly decrease risk of
mortality (esp. CVD mortality) in persons with diabetes
Americans consume 4-5 times as much saturated fat
as trans fat
Maximum Daily Amount of Saturated Fat
Total Calorie Intake
Limit on Saturated Fat Intake
1,600
18 g or less
2,000
20 g or less
2,200
24 g or less
2,500
25 g or less
2,800
31 g or less
Amount keep levels below 10% of total calories
Rounded to nearest 5 grams to be consistent with Nutrition Facts
Panel
Table 8 and Table 9 of Dietary Guidelines
Nutrition Facts Label – Saturated Fat
% Daily Value for Saturated
Fat
5% or less is low
20% or more is high
Dietary Guidelines Recommendation –
Adults with Elevated LDL
Less than 7% of calories from saturated fat
Less than 200mg/day from cholesterol
Should be under care of physician
Trans Fatty Acids
Dietary Guidelines
– “…..keep trans fatty acid consumption as low as possible”
Primarily found in processed foods and oils and
animal products
– Partially hydrogenated oils and foods containing partially
hydrogenated oils
Reasons for hydrogenating
– Shelf stable
– Withstands repeated heatings without breaking down
– Oil becomes solid at room temperature
Trans Fatty Acids & Heart Disease
Increases risk of CHD
– Increases LDL cholesterol
– Lowers HDL cholesterol
– Increases tendency of blood platelets to clump
Harvard University study estimates that replacing
partially hydrogenated fat with healthy unsaturated
vegetable oils would prevent at least 30,000
premature deaths from heart disease each year
Trans Fat in the American Diet
Americans consume 4-5 times as much saturated fat as
trans fat
Average intake = 5.84 grams
2.6% of total calories (estimated at 4-7% in early 1990’s)
80% is from processed foods and oils compared to 20%
from animal sources (naturally occurring trans fat)
FDA once estimated that 95% of prepared cookies, 100% of
crackers and 80% of frozen breakfast products contained
trans fat
Trans fat in processed foods has changed and is likely to
continue to change as the industry reformulates products
Trans Fat in the American Diet*
Food Group
Contribution
(% of total trans fat consumed)
Cakes, cookies, crackers, pies, bread, etc.
40
Animal products
21
Margarine
17
Fried Potatoes
8
*Data collected 1994-1996
Table 11
McDonald’s French Fries
Size
Trans fat (g)
Small
3.5
Medium
5
Large
8
Ingredients: Potatoes, partially hydrogenated soybean oil, natural flavor (beef,
wheat and dairy sources), dextrose, sodium acid pyrophosphate (to preserve
natural color).
Cooked in partially hydrogenated vegetable oils (may contain partially
hydrogenated soybean oil and/or partially hydrogenated corn oil and/or partially
hydrogenated canola oil and/or cottonseed oil and/or sunflower oil and/or corn
oil).
Nutrition Facts Label – Trans Fat
As of January 1, 2006 the FDA requires
on Nutrition Facts Label
No %DV for trans fat
Choose products with little or no trans
fat
When comparing products:
Add grams of saturated fat and trans fat
McDonald’s French Fries
Size
Saturated Fat (g)
Trans fat (g)
Small
2.5
3.5
Medium
4
5
Large
6
8
Ingredients: Potatoes, partially hydrogenated soybean oil, natural flavor (beef,
wheat and dairy sources), dextrose, sodium acid pyrophosphate (to preserve
natural color).
Cooked in partially hydrogenated vegetable oils (may contain partially
hydrogenated soybean oil and/or partially hydrogenated corn oil and/or partially
hydrogenated canola oil and/or cottonseed oil and/or sunflower oil and/or corn
oil).
Trans Free Products
Soon to Limit Trans Fat….
Cholesterol
Dietary Guidelines
– “Consume less than 300mg/day of cholesterol….”
– “Because men tend to have higher intakes of dietary
cholesterol, it is especially important for them to meet this
recommendation.”
– Individuals with elevated LDL should consume less than 200mg/day
of cholesterol
ONLY found in animal products
– Often found in animal products high in saturated fat
Linked to increased LDL cholesterol and CHD
National Cholesterol Education Program
ATPIII Cholesterol Recommendations - 2001
Total Cholesterol
Less than 200
200-239
Greater than 240
Desirable
Borderline High
High
LDL Cholesterol
Less than 100
100-129
130-159
160-189
Greater than 190
Optimal
Near or above optimal
Borderline High
High
Very high
HDL Cholesterol
Less than 40
Greater than 60
Undesirable
Desirable
Triglycerides
Less than 150
150-199
200-499
Greater than 500
Normal
Borderline High
High
Very High
Women’s Health Initiative Study
Reducing Total Fat Intake
Study the effect of low-fat, high fruit, vegetable, and
grain diet on breast cancer, colorectal cancer and
heart disease in postmenopausal women
Diet NOT designed for weight loss
Women followed 8.1 years
48,000 postmenopausal woman
– No intervention – 60% of participants
– Intervention (dietary change) – 40% of participants
WHI - Dietary Change Group Goals
Decrease fat intake to 20% of total calories
Increase fruits and vegetables to 5 or more servings/day
Increase grains to 6 or more servings/day
Methods for dietary changeAttended group sessions (included education)
– 18 time in year one
– 4 times in year 2-8
Self-monitoring
WHI - % Calories from Fat
Dietary Change
Group
No
Intervention
Difference
Study Goal
20%
Baseline
35%
35%
0%
At 1 year
24%
35%
11%
At 6 years
29%
37%
8%*
2.9% decrease saturated fat
3.3% decrease monounsaturated fat
1.5% decrease polyunsaturated fat
WHI – Fruits and Vegetables and Grains
Fruits and Vegetables
– Dietary Change Group 3.5 to 5 servings at year 1 and year 6
– Comparison Group 3.5 to 4 servings at year 1 and year 6
Grains
– 4.5 servings at baseline for both groups
– Very little change in either group over time
WHI – Breast Cancer
9% lower rate in women in Dietary Change group which was not
quite statistically significant
Women who had higher levels of dietary fat intake at the start of
the study had a greater reduction in fat and a greater reduction
in risk (15-20%)
Women who most strictly adhered to 20% fat intake had 15-20%
risk reduction
Low fat diet reduced blood estradiol (estrogen) by 15% (breast
cancer risk factor)
30% risk reduction for a certain subtype of breast cancer
– Progesterone-receptor negative tumors (rare)
WHI – Breast Cancer Possible Explanations
Insufficient follow-up time
Dietary fat not low enough (did not meet the goal)
WHI – Colorectal Cancer
Did not reduce risk
9% lower reporting of polyps in Dietary Change
group
No benefit found in those that adhered to low-fat goal
No benefit found in those that had greatest decrease
in fat
Possible benefit due to decrease polyps if followed
for longer period of time
WHI – Heart Disease
Did not reduce risk of heart disease (look at heart
attacks and death from heart disease)
Small but significant improvements in risk factors
including:
–
–
–
–
Body weight
LDL
Diastolic blood pressure
Factor VII C (a blood clotting factor)
Women who reached lowest levels of saturated and
trans fat and highest level of fruits and vegetables
had greater reductions in LDL (but lower sample size)
WHI – Heart Disease Explanations
Dietary pattern reduced ALL types of fat since trying
for low fat diet to determine impact on breast cancer
Diet designed for heart disease would focus on
reducing saturated and trans fat
Relied on food frequency questionnaires which rely
heavily on memory*
Length of study*
Participants started the study late in life*
Key Lessons
Greatest changes in fats were made by decreasing added
fats
Dietary change and maintaining change strongly
associated with attending nutritionist-led groups and selfmonitoring food intake
Results show it is feasible to reduce fat intake to below
30%
Low-fat, high carbohydrate diet does not increase body
weight, blood triglycerides, or indicators of increased risk
of diabetes such as blood glucose or insulin levels