lipids:’...

Lipids: Role in Exercise and Recovery

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Outline

I. Lipids: Basics A.  Lipid composi6on; fa9y acids B.  Diges6on C.  Absorp6on and transport D. Metabolism E.  Synthesis F.  Storage

II.  Lipids for energy and health A.  Energy yield B.  Recommended intake C.  Coronary heart disease D.  Thermogenesis E.  Insula6on F.  Cancer

III. Op6mizing lipid intake: Ergonomic strategies for exercise performance A.  Fat loading B.  Dietary changes C.  Supplements

V. Appendix A.  Dietary sources of fat

I. Lipids:

Basics

Lipids in Diet

§  Lipids are organic molecules (generally not soluble in water) that are found in the diet as –  Fats

•  Solid at room temperature

•  Derived primarily from animals

–  Oils •  Liquid at room temperature (except coconut oil)

•  Derived primarily from plants

Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins, 2010.

Lipid Composi<on

§  Lipids are composed of a glycerol molecule and at least 1 fa9y acid molecule –  Maximum of 3 fa9y acids can bind to glycerol

5 Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins, 2010.

Lipid Composi<on: Fa>y Acid Structure

§  Fa9y acids are defined by their structure, which characterizes their biologic ac6vity –  The number of carbon atoms (C) in the chain (typically, 12 to 24)

•  Short: < 6 carbon atoms •  Medium: 6-‐10 carbon atoms •  Long: ≥ 12 carbon atoms

–  The double bonds between carbon atoms in the chain •  Saturated (none)

–  Solid at room temperature

•  Unsaturated (at least 1) –  Liquid at room temperature

•  Delta (Δ) versus omega (ω) carbons to denote first double bond •  Cis versus trans carbon bond a9achment

–  Trans bond is less common in nature, but produced industrially for food (par6ally hydrogenated fats)


Trans double bond

Cis double bond

Physiologically Relevant Fa>y Acids

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Carbons: Double bonds Common Name Function

14:0 Myristic acid

Attached to plasma membrane-associated cytoplasmic proteins

16:0 Palmitic acid

End product of mammalian fatty acid synthesis

16:1Δ9 Palmitoleic acid

May protect against insulin resistance (from endogenous fat synthesis and dairy products)

18:0 Stearic acid Component of phospholipids

18:1Δ9 Oleic acid

Most abundant fatty acid in adipose tissue

18:2Δ9,12 Linoleic acid Essential fatty acid

18:3Δ9,12,15 α-Linolenic acid Essential fatty acid

20:4Δ5,8,11,14 Arachidonic acid

Precursor for eicosanoid synthesis (prostaglandins, thromboxanes, and leukotrienes for growth, wound healing, and skin)

20:5Δ5,8,11,14,17 Eicosapentaenoic acid (EPA)

Modifies triglyceride levels, potentially decreasing risk of cardiovascular disease (in fish oils)

22:6Δ4,7,10,13,16,19 Docosahexaenoic acid (DHA)

Modifies triglyceride levels, potentially decreasing risk of cardiovascular disease (in fish oils)

Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins, 2010. Mozaffarian D, et al. Ann Intern Med. 2010; 153:790-‐799.

Lipid Types

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§ Average triglyceride –  Glycerol plus 3 fa9y acids (most

abundant) •  Monoglyceride: 1 fa9y acid •  Diglyceride: 2 fa9y acids

§ Phospholipids –  Glycerol + 2 fa9y acids +

phosphate group

§ Biologic substances that either contain lipid or need lipids for proper func6on –  Cholesterol –  Hormones –  Fat-‐soluble vitamins –  Lipoproteins

Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins, 2010.

Lecithin, phospholipid

Factors Affec<ng Fat Absorp<on/Metabolism § Age

–  Does not affect capacity to absorb fat •  Gastrointes6nal transit 6mes are similar between healthy younger and older adults

§  Exercise –  Effects of exercise on fat metabolism are influenced by exercise type,

intensity, and dura6on and by fitness level of individual –  In general, light to moderate exercise increases fat oxida6on

•  Intensive exercise reduces fat oxida6on § Gene6c

–  Suscep6bility to weight gain and obesity •  Reduced ability to increase fat oxida6on in the presence of fa9y meals

§ Alcohol –  Oxidized to acetyl CoA and can enter into fa9y acid synthesis

•  Inhibits fa9y acid oxida6on and any excess energy shins towards storage

9

Panel on Macronutrients, Subcommi9ees on Upper Reference Levels of Nutrients and Interpreta6on and Uses of Dietary Reference Intakes, and the Standing Commi9ee on the Scien6fic Evalua6on of Dietary Reference Intakes. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fa9y Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). The Na6onal Academies Press. 2005; Jeukendrup AE. Sportmedizin und Spor:raumatologis. 2003;51(1):17-‐23.

Lipid Diges<on

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§  Mouth lipases –  Start breakdown of large lipid globules into

smaller droplets

§  Stomach lipases –  Complete breakdown of lipid globules into

droplets

§  Intes6ne –  Bile salts emulsify the lipid droplets into smaller

por6ons –  Pancrea6c lipases can now break the lipids into

components (fa9y acids, monoglycerides, glycerol, and free cholesterol)

–  Lipid components form micelles –  At the border of intes6nal cells, the bile salts

disperse from the micelle, allowing the lipid components to be absorbed

Lipid Absorp<on

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§  Medium-‐ and short-‐chain free fa9y acids are absorbed and directly enter blood

§  Monoglycerides and cholesterol have to be processed

§  Triglycerides join cholesteryl esters and apolipoprotein B (apoB) to form chylomicrons –  Secreted into the lymph before reaching the blood circula6on

§  Tissues remove triglycerides from chylomicrons

§  The liver absorbs remainder of chylomicron

Shi Y and Cheng D. Am J Physiol Endocrinol Metab. 2009;297:E10-E18.

Nutritional relevance: Excess fatty acids are stored in adipose tissue for energy; adequate stores of appropriate

fatty acids are needed for muscle energy

Lipid Transport

§  Lipids (triglycerides) are packaged by the liver into very-‐low-‐density lipoproteins (VLDL) and released into the circulatory system –  At the capillary walls of 6ssues,

VLDLs release triglycerides and can take up cholesterol (becoming low-‐density lipoprotein [LDL]) •  The LDL receptors in the liver remove LDL from the circula6on

•  High-‐density lipoproteins can also take up unused cholesterol and transport it back to the liver

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Lipid Metabolism: Overview

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§  Triglycerides from the liver or chylomicrons are digested by 6ssue lipases into free fa9y acids and glycerol

§ β-‐oxida6on of fa9y acids in cell mitochondria is the primary pathway to produce energy from fats

§ Unsaturated fa9y acids also undergo β-‐oxida6on –  ATP yield is less due to presence of double bonds

§  Fat oxida6on is regulated by insulin and citrate (inhibits) and glucagon and epinephrine (s6mulates) –  Whenever fa9y acid metabolism is s6mulated, synthesis is inhibited

and vice versa

§ Mammals cannot metabolize fa9y acids to glucose

ATP, adenosine triphosphate. Driskell JA. Sports Nutri>on. Boca Raton, FL: CRC Press, LLC; 2000. Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co.; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins; 2010.

Lipid Metabolism: Ketone Bodies

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§ Ketone bodies form when carbohydrates are low or not available (in fas6ng or diabe6c condi6ons)

§ Ketone bodies are used by the heart muscle and renal cortex as fuel over glucose, although fa9y acids are the primary fuel source –  Ketones and lactate can be used during 6mes of stress –  Brain can also use ketone bodies as fuel during starva6on

(adap6ve mechanism; brain normally prefers glucose)

§  Large amounts of ketone bodies in the blood lead to –  Inhibi6on of lipid metabolism –  Acidosis of the blood –  Forma6on of acetone from acetoacetate (spontaneous and

irreversible reac6on)

§  Excreted in urine Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co.; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins; 2010.

Lipid Metabolism: Medium-‐Chain Triglycerides/Fa>y Acids

§ Medium-‐chain fa9y acids are ~10 to 12 carbons or less § Poten6al alternate energy source for working muscles, but a key problem is geung these fa9y acids to peripheral 6ssues –  Poten6al solu6on: Structured triglyceride

•  Alters structure for easier transport to peripheral 6ssues

Bach AC and Babayan VK. Am J Clin Nutr. 1982;36(5):950-‐962.

Nutritional relevance:

Short- and medium-length fatty acids are readily available; directly absorbed from the intestine into the blood

Metabolized more like a carbohydrate than a fat

Metabolism of Fat for Energy: Key Summary Points

§ Pros: –  ATP yields are very large for fa9y acids versus glucose –  Very dense energy reserve (3,500 kcal = 1 lb body fat) – May benefit primarily Type I “slow twitch” muscle fibers that mainly burn fat as energy

§ Cons: –  Requires oxygen – Metabolizing fats is not as quick as for carbohydrates –  Training required to enhance the body’s ability to access fat for energy during exercise •  Because slow endurance ac6vi6es may best u6lize stored fat, fast metabolism of fats may not be relevant

16 Abbrevia6on: ATP, adenosine triphosphate.

Fat Synthesis: Overview

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§  Sources for lipids for body fat: –  Dietary –  Fa9y acids from other fa9y acids

•  Primarily occurs in the liver

–  De novo lipogenesis (minor pathway in humans) •  Primarily occurs in the liver •  Fa9y acids from other precursors (ie, carbohydrates) •  Acetyl CoA is the star6ng molecule

–  Fa9y acid chain is built 2 carbons at a 6me un6l it reaches 16 carbons

Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co.; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins; 2010.

Lipid Storage

§  Adipose is connec6ve 6ssue specialized for lipid storage in the form of triglycerides –  Requires glucose to convert free fa9y acids

to triglycerides

§  Adipose can be “white” or “brown” –  White adipose 6ssue has several func6ons

•  Energy source

•  Hormonal (eg, lep6n and estrogen)

•  Insula6on

•  Mechanical cushion

•  Buoyancy

–  Brown adipose 6ssue generates heat •  More metabolically ac6ve

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ER, endoplasmic re6culum. Albright AL and Stern JS (1998). Adipose 6ssue. In: Encyclopedia of Sports Medicine and Science, Fahey TD (ed). Internet Society for Sport Science: h9p://sportsci.org. 30 May 1998. Berg JM, et al. Biochemistry. 5th ed. New York, NY: WH Freeman and Co.; 2002. Harvey RA and Ferrier DR. Biochemistry. 5th ed. Lippinco9 Williams & Wilkins; 2010.

II. Lipids for Energy and Health

Lipids for Energy

§  In general, 1 g fat is converted to 9 Calories (kcals)1 § Whole body fat breakdown in healthy individuals is ~1 mg/kg/min (~100 g fat/day)2 –  Typical Western dietary intake of fat is ~100 g/day

•  Direct storage of fat is ~50% of intake; rest is oxidized for energy •  Triglyceride turnover in adipose cells is ~6 months

§ Res6ng metabolic rate of skeletal muscle is ~13 kcal/kg/day3 –  Comparison with other 6ssues

•  Body fat, 4.5 kcal/kg/day •  Brain, 240 kcal/kg/day •  Heart, 440 kcal/kg/day

–  However, wide variability among individuals exists

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1. Driskell JA. Sports Nutri>on. Boca Raton, FL: CRC Press, LLC.; 2000. 2. Strawford A, et al. Am J Physiol Endocrinol Metab. 2004;286:E577-‐E588. 3. Wang Z, et al. Am J Clin Nutr. 2010;92(6):1369-‐1377.

Lipids: Recommended Intake (1 of 2) §  Total fats

–  No Adequate Intake, Recommended Dietary Allowance, or tolerable Upper Intake Level is set; lack of data

–  Acceptable Macronutrient Distribu6on Range is 20% to 35% of energy (Calories)

§  Saturated and Trans fa9y acids –  No Adequate Intake or Recommended Dietary Allowance is set; no

role in disease preven6on, and saturated fats are synthesized by the body

–  No tolerable Upper Intake Level is set; any increase in intake raises risk of coronary heart disease •  Limit saturated fat intake to 7% to 10% of kcals; typical Western diet provides 11% –  0% intake is not advised and probably not possible

•  Limit trans fa9y acid intake to as low as possible, preferably <1% of energy –  Less than 0.5 g may be labelled as 0 g trans fat

21

Panel on Macronutrients, Subcommi9ees on Upper Reference Levels of Nutrients and Interpreta6on and Uses of Dietary Reference Intakes, and the Standing Commi9ee on the Scien6fic Evalua6on of Dietary Reference Intakes. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fa9y Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). The Na6onal Academies Press; 2005. Na6onal Cancer Ins6tute. Sources of saturated fat in the diets of the U.S. popula6on ages 2 years and older, NHANES 2005–2006. Risk Factor Monitoring and Methods. Cancer Control and Popula6on Sciences. Available at: h9p://riskfactor.cancer.gov/diet/foodsources/sat_fat/sf.html. Lichtenstein AH, et al. Circula>on. 2006;114:82-‐96. Labeling guide for trans fat available at: h9p://www.fda.gov/Food/GuidanceComplianceRegulatoryInforma6on/GuidanceDocuments/FoodLabelingNutri6on/FoodLabelingGuide/ucm064904.htm#transfat.

Lipids: Recommended Intake (2 of 2) §  Polyunsaturated fa9y acids (PUFAs)

–  6% to 11% of kcals from PUFAs is recommended due to poten6al for oxida6on of lipoproteins; intakes above recommenda6ons may increase risk of some cancers

–  Omega-‐6 •  Primarily linoleic acid from dietary sources •  Tends to have greater cholesterol and LDL-‐lowering effects than monounsaturated fa9y acids •  May lower HDL-‐C when subs6tuted for saturated fa9y acids

–  Omega-‐3 •  1 serving of fish (preferably oily) twice a week

–  Fish oil supplements may be taken by pa6ents with coronary heart disease or elevated triglycerides

•  Can modestly elevate LDL-‐C levels (DHA; EPA is neutral) §  Linoleic acid (an essen6al omega-‐6 PUFA)

–  Adequate Intake is 17 g/day for men and 12 g/day for women •  Typical Western diet provides Adequate Intake

–  No tolerable Upper Intake Level is set; lack of data §  α-‐linolenic acid (an essen6al vegetable omega-‐3)

–  Adequate Intake is 1.6 g/day for men and 1.1 g/day for women •  Typical Western diet provides Adequate Intake

–  No tolerable Upper Intake Level is set; lack of data

22

EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid. Panel on Macronutrients, Subcommi9ees on Upper Reference Levels of Nutrients and Interpreta6on and Uses of Dietary Reference Intakes, and the Standing Commi9ee on the Scien6fic Evalua6on of Dietary Reference Intakes. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fa9y Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). The Na6onal Academies Press; 2005. Na6onal Cancer Ins6tute. Available at: h9p://riskfactor.cancer.gov/diet/foodsources/sat_fat/sf.html. American Heart Associa6on. Fish 101. Available at: h9p://www.heart.org/HEARTORG/GeungHealthy/Nutri6onCenter/Fish-‐101_UCM_305986_Ar6cle.jsp. FAO/WHO Expert Consulta6on. Available at: h9p://www.who.int/nutri6on/topics/FFA_summary_rec_conclusion.pdf. Wei MY, et al. Curr Atheroscler Rep. 2011;13(6):474-‐483.

0

0

0

0

0

0

0

0

0

0

0

0

12

14

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Cholesterol, mg/tbsp

Dietary fat Breakdown of fa9y-‐acid content (normalized to 100%)

Propor<ons of Fa>y Acids in Dietary Sources

23 Data from Wardlaw GM, Hampl JS, Disilvestro RA. Perspec>ves in Nutri>on, 6th ed. New York: McGraw-‐Hill; 2003.

Dietary Cholesterol and Blood Cholesterol Levels

§  Dietary intake of cholesterol has a weak associa6on with blood cholesterol levels –  Majority of cholesterol is synthesized by the body

•  10% in the liver, 15% in the intes6nes, and the rest throughout the body –  Liver uses saturated fa9y acids to synthesize cholesterol

–  Type of dietary fat consumed has larger influence on blood cholesterol levels •  However, some people have a strong blood cholesterol response to dietary

cholesterol intake and are called “responders” –  Dietary cholesterol may act synergis6cally with saturated fat to increase

LDL-‐C levels §  AHA, NCEP ATP III recommend dietary cholesterol intake

–  < 300 mg/day in a normal diet –  < 200 mg/day to reduce risk of CHD

LDL-‐C, low-‐density lipoprotein-‐cholesterol; NCEP, Na6onal Cholesterol Educa6on Program. Harvard School of Public Health. The Nutri6on Source Fats and Cholesterol. Available at: h9p://www.hsph.harvard.edu/nutri6onsource/what-‐should-‐you-‐eat/fats-‐full-‐story/index.html. Expert panel of detec6on, evalua6on, and treatment of high blood cholesterol in adults, JAMA. 2001;285(19):2486-‐2497. American Heart Associa6on (AHA). Diet and Lifestyle Recommenda6ons. Available at: h9p://www.heart.org/HEARTORG/GeungHealthy/Diet-‐and-‐Lifestyle-‐Recommenda6ons_UCM_305855_Ar6cle.jsp. Fielding CJ, et al. J Clin Invest. 1995;95:611-‐618. The Medical Biochemistry Page. Available at: h9p://themedicalbiochemistrypage.org/cholesterol.html.

Cholesterol itself is not good or bad; how it is transported is the main concern for health effects

Lipid Func<ons in the Body for Health § Dietary lipids, as fat, have many func6ons in the body besides providing energy –  Mechanical: insula6on, cushion, and buoyancy –  Sa6ety factor (longer 6me to digest) –  Transport and storage of fat-‐soluble vitamins (A, D, E, and K) –  Components of cell membranes, re6na, and hormones

§  Lipid levels in the body influence risk of cardiovascular disease and possibly cancer

25 Driskell JA. Sports Nutri>on. CRC Press, LLC.; Boca Raton, FL; 2000.

Unsaturated fatty acid intake can improve lipid parameters, potentially decreasing cardiovascular risks, whereas saturated fatty acids have the

opposite effect

Industrial trans fatty acid intake can adversely affect lipid parameters, potentially increasing cardiovascular risks, whereas cis fatty acid intake

is lipid neutral

Lipid Intake and Healthy Values for Lipid Parameters

§  Increasing lipid intake leads to increased values for blood lipid parameters –  In general, saturated fa9y acids are be9er at increasing lipid parameters

than monounsaturated or polyunsaturated fa9y acids •  For every 1% energy increase from saturated fa9y acids

–  LDL-‐C values ↑ ~0.04 mmol/L (~1.5 mg/dL) –  HDL-‐C values ↑ ~0.01 mmol/L (~0.4 mg/dL)

•  However, not all saturated fa9y acids are equal –  Stearic acid has neutral effects on lipid parameters –  Palmi6c, lauric, and myris6c acids increase cholesterol levels

–  Trans fa9y acids act similarly to saturated fa9y acids on LDL-‐C levels •  HDL-‐C levels increase slightly or decrease, resul6ng in a worse LDL-‐C:HDL-‐C ra6o compared with saturated fa9y acids

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LDL-‐C, low-‐density lipoprotein-‐cholesterol; HDL-‐C, high-‐density lipoprotein-‐cholesterol. Panel on Macronutrients, Subcommi9ees on Upper Reference Levels of Nutrients and Interpreta6on and Uses of Dietary Reference Intakes, and the Standing Commi9ee on the Scien6fic Evalua6on of Dietary Reference Intakes. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fa9y Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). The Na6onal Academies Press. 2005. Hayes KC, et al. Prostaglandins Leukot Essent Fa:y Acids. 1997;57(4-‐5):411-‐418.

Lipid Effects From Dietary Meat Intake §  Intake of lean red meat (< 10% total fat) does not increase cholesterol levels or risk of thrombosis –  Beef, veal, or lamb

§  Lean red meat and lean white meat (chicken and fish) have similar effects on lipid parameters –  Decrease LDL-‐C and total cholesterol levels –  Lean beef had results similar to a soybean-‐based diet

§ Consuming a higher ra6o of visible meat fat to meat increases total serum cholesterol and LDL-‐C levels –  HDL-‐C levels are unaffected

27 Abbrevia6ons: LDL-‐C, low-‐density lipoprotein-‐cholesterol; HDL-‐C, high-‐density lipoprotein-‐cholesterol. Li D, et al. Asia Pac J Clin Nutr. 2005;14(2):113-‐119.

Lean meat may have beneficial effects on lipid parameters

Values for Lipid Parameters

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Total cholesterol, mg/dL <200 200-‐239 ≥240

Desirable Borderline high High

LDL cholesterol, mg/dL <100 100-‐129 130-‐159 160-‐189 ≥190

Op6mal, unless very high CHD risk Near or above op6mal Borderline high High Very high

HDL cholesterol, mg/dL <40 ≥60

Low (high CHD risk) High (low CHD risk)

Triglycerides, mg/dL <150 150-‐199 200-‐499 ≥500

Normal Borderline high High Very high

CHD, coronary heart disease. NCEP ATP III. JAMA. 2001;285(19):2486-‐2497.

Factors Influencing Goals for Abnormal Lipid Parameters § Goals for abnormal lipid parameters depend on

–  Es6mated 10-‐year risk of coronary heart disease (CHD) •  Online tool for es6ma6ng risk: h>p://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=prof

–  Presence of risk factors for CHD, including •  Atherosclero6c disease •  Diabetes •  Smoking •  Hypertension •  Family history of premature CHD •  Age (men ≥45 y; women ≥55 y) •  HDL-‐C levels <40 mg/dL

–  HDL-‐C levels ≥60 mg/dL is a nega6ve risk factor and, if present, can remove 1 risk factor from total count

29 NCEP ATP III. JAMA. 2001;285(19):2486-‐2497.

Fate of Dietary n-‐3 Versus n-‐6 Fa>y Acids

§  Fa9y acids are used by the body in the produc6on of eicosanoids (local hormones) §  Important in inflamma6on, blood flow, nerve signaling, and transport across cell membranes

§ Omega-‐3 fa9y acids promote the development of eicosanoids that are par6cularly heart healthy and improve inflamma6on §  Omega-‐6 fa9y acids tend to produce eicosanoids that are less an6-‐inflammatory

§  Fish oils, as a source of omega-‐3 fats, can also reduce triglyceride levels

§  The Western diet typically contains a high amount of omega-‐6 and less omega-‐3


Alcohol and Coronary Heart Disease

§ 1 to 2 drinks/day may be associated with decreased risk of CHD and CHD mortality1,2 –  ~20 g of ethanol/day for men and 10 g/day for women –  Wine has an6oxidants and is preferred to alcoholic drinks without

an6oxidants (eg, dis6lled alcohol) §  Effects of low-‐to-‐moderate alcohol intake on lipids tend toward3,4

–  Increased HDL-‐C levels •  However, triglyceride levels tend to increase also

–  Decreased total LDL-‐C levels –  Wide varia6ons exist, and individual responses cannot be predicted

1.  Roerecke M and Rehm J. Addic>on. 2012. doi: 10.1111/j.1360-‐0443.2012.03780.x. [Epub ahead of print]. 2.  Di Minno MN, et al. Semin Thromb Hemost. 2011;37(8):875-‐884. 3.  Kuusisto SM, et al. Ann Med. 2011. [Epub ahead of print]. 4.  Mukamal KJ, et al. J Clin Endocrinol Metab. 2007;92(7):2559-‐2566.

III. Op<mizing Lipid Intake:

Ergonomic Strategies for Exercise Performance

Adapta<ons to Fat Metabolism From Exercise §  Overall, exercise improves

–  Blood flow •  Increases hemoglobin and myoglobin to store oxygen •  Increases mobiliza6on and transporta6on of fa9y acids

–  Mitochondrial number in skeletal muscles •  Increases oxida6on of fa9y acids for energy

§  Endurance athletes have a high capacity for fat oxida6on compared with those who have had no training at similar rela6ve exercise intensi6es

§  Because fa9y acids are efficiently used by trained athletes, increasing fa9y acid intake before an event may enhance exercise performance

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Jeukendrup AE. Sportmedizin and Spor:raumatologie. 2003;51(1):17-‐23; Mar6n WH, 3rd. Exerc Sport Sci Rev. 1996;24:203-‐231; Coleman E for Nutri6on Dimension 2010. Available at: h9p://www.nutri6ondimension.com/index.tpl?inpage=course_descript&incourse=FLE10-‐F&extraTop=T. Maughan R and Bruke L. Sports Nutri6on: More Than Just Calories–Triggers for Adap6on. 69th Nestle Nutri6on Ins6tute Workshop, Kona, Hawaii; October 2010.

Ergogenic Lipid Strategies for Exercise Endurance Performance §  Fat loading

–  Short-‐term –  Long-‐term

§ Dietary changes –  High-‐fat diet –  Low-‐fat diet –  Mediterranean diet

§  Supplements –  Medium-‐chain triglycerides –  Omega-‐3 –  Conjugated linoleic acid

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Fat Loading/Adapta<on: Short-‐ and Long-‐Term

§  Spares CHOs and/or slows the rate of CHO use during prolonged exercise

§  More energy can be stored per pound of fat than glycogen

§  Prolonged, low-‐intensity exercise favors lipid oxida6on

§  Enhances lipid storing and metabolism –  However, reduces op6mal glycogen

metabolism

Abbrevia6on: CHO, carbohydrate. Ornish D, et al. JAMA. 1998;280(23):2001-‐2007; Lichtenstein AH, et al. Circula>on. 1998;98:935-‐939.

§  High variability between individuals in developing fat oxida6on adapta6ons from a high-‐fat diet

§  High-‐fat diets can be low in carbohydrates, leading to reduced glycogen stores –  Training at higher intensi6es may be difficult

PROs CONs

Fat Loading/Adapta<on: Summary of Evidence §  Increased fat adap6on was suggested by studies §  Improved overall performance and mean power output were noted in some studies, but results were not sta6s6cally significant

§  The hypothesis that fat loading/adapta6on improves performance and/or low-‐intensity endurance remains controversial

§  Further suppor6ve evidence from several adequately powered, well-‐designed studies would be required to recommend this approach for endurance athletes

36

Coleman E. Fat Loading for Endurance Sports. 2010 ed. Available at: www.Nutri6onDimension.com; Yeo WK, et al. Appl Physiol Nutr Metab. 2011;36(1):12-‐22; Lambert EV, et al. Eur J Appl Physiol. 2994;69:287-‐293; Burke LM, et al. J Appl Physiol. 2000;89:2413-‐2421; Burke LM, et al. Med Sci Sports Exerc. 2002;83-‐91; Carey AL, et al. J Appl Phys. 2001;91:115-‐122; Sherman WM and Leenders N. Int J Sport Nutr. 1995;5(suppl):S1-‐12; Jeukendrup AE. Sportmedizin and Spor:raumatologie. 2003;51(1):17-‐23.

Difficult to achieve a high fat intake and high glycogen levels in the context of an isocaloric diet (ie, energy intake matches expenditure)

Dietary Changes: High-‐Fat Diet

§  Increasing fa9y acid intake, while maintaining carbohydrate intake, may improve endurance –  Increase fats from 15% to

30%-‐42% of calories

Ornish D, et al. JAMA. 1998;280(23):2001-‐2007; Lichtenstein AH, et al. Circula>on. 1998;98:935-‐939. Pendergast DR, et al. J Am Coll Nutr. 2000;19(3):345-‐350.

§  Increases cholesterol levels, if fat intake is the wrong type

§ Role of body fat distribu6on in fa9y acid oxida6on and exercise endurance

§ Role of muscle fiber composi6on in determining fa9y acid oxida6on rate

§  Effects on cardiac output and risk of cardiovascular disease

PROs CONs

Uncertainties

Dietary Changes: Low-‐Fat Diet (<20% Energy)

§  May increase insulin sensi6vity and glucose uptake by the muscle cells

§  Postpones fa6gue §  Increases endurance dura6on and

performance §  Restora6on of muscle glycogen

levels can be faster §  Reduce body fat

Abbrevia6on: HDL-‐C, high-‐density lipoprotein-‐cholesterol; MUFA, monosaturated fa9y acid. Ornish D, et al. JAMA. 1998;280(23):2001-‐2007; Lichtenstein AH, et al. Circula>on. 1998;98:935-‐939. Pendergast DR, et al. J Am Coll Nutr. 2000;19(3):345-‐350.

§  May nega6vely affect metabolic profile; strong evidence does not exist –  Increased triglycerides –  Decreased HDL-‐C –  Increased response in postprandial glucose and insulin levels

§  Lower testosterone and estrogen levels §  Vitamins A, D, E, and K may not be properly absorbed

§  Lower calorie intake §  Deficiency in other nutrients §  Impaired performance over 6me (compared with op6mal for individual)

§  Possible inadequate intake of beneficial fats (eg, omega-‐3 and MUFA)

PROs CONs

Dietary Changes: Very Low-‐Fat Diet (Dean Ornish)

§  Reduc6on of LDL-‐C levels §  Regression of atherosclerosis

Abbrevia6ons: LDL-‐C, low-‐density lipoprotein-‐cholesterol; HDL-‐C, high-‐density lipoprotein-‐cholesterol. Ornish D, et al. JAMA. 1998;280(23):2001-‐2007; Lichtenstein AH, et al. Circula>on. 1998;98:935-‐939.

§  Very radical dietary change –  Need a very motivated person and medical

monitoring –  Substituting complex carbohydrates for fat

and preserving protein intake is required §  Nutritional inadequacy (protein, iron, B12,

and calcium) §  American Heart Association did not

recommend this diet in 1998 –  Long-term results are needed for benefit

statement –  May observe increased triglyceride levels,

but attenuated by high fiber intake –  May observe decreased HDL-C levels

PROs CONs

Dietary Changes: Mediterranean-‐Style Diet

40 The Mediterranean-‐diet-‐for-‐all organiza6on. Available at: h9p://www.mediterraneandie�orall.com/.

§  Higher in omega-‐3, an6oxidants, and fiber than a Western diet

§  Lowered intake of fat and red meat

§  May have limited access to foods that are common in this culture

§  May be hard to adapt to culture tastes

PROs CONs

§  Red meat: 1 6me a month

§  Poultry: 2 to 3 6mes a week –  Dairy in modera6on

§  Fish: 2 to 3 6mes a week

§  Fruit and vegetables: 5 to 6 servings/day –  Olive oil replaces bu9er and almost all other oils (can

use other oils high in monounsaturated fa9y acids)

Dietary Changes: Summary of Evidence § An isocaloric diet should contain 25% to 35% fats

–  For exercise intensi6es of up to 85% of VO2max, dietary fats may be more beneficial

–  For exercise intensi6es above 100% of VO2max, carbohydrates would be preferred

–  Intake of fats versus carbohydrates to op6mize exercise performance between 80% to 100% VO2max is unclear

§  Example –  70-‐kg athlete taking in 3,500 kcals/day

•  25% fat would be 875 kcals (97 g) from fat per day •  35% fat would be 1,225 kcals (136 g) from fat per day

41 Pendergast DR, et al. J Am Coll Nutr. 2000;19(3):345-‐350.

Dietary Supplements: Medium-‐Chain Triglycerides

42

Lowry LM. J Sport Sci Med. 2004;3:106-‐117; Berning JR. Int J Sport Nutr. 1996;6(2):121-‐133. Kern M, et al. J Nutr Biochem. 2000;11(5):288-‐292; Berning JR. Int J Sport Nutr. 1996;6(2):121-‐133.; Horowitz JF, et al. J Appl Physiol. 2000;88:219-‐225; Jeukendrup AE, et al. Am J Clin Nutr. 1998;67:397-‐404. Gomes RV and Aoki MS. Rev Bras Med Esporte. 2003;9(3):162-‐168; Goedecke JH, et al. Metabolism. 1999;48(12):1509-‐1517; Misell LM, et al. J Sports Med Phys Fitness. 2001;41(2):210-‐215.

§  Oral, water-‐soluble §  Easily absorbed

–  Readily available for muscle cell uptake

§  Easily oxidized (as quickly as glucose)

§  Theore6cally, promotes muscle glycogen sparing

§  Lipid profile may be nega6vely affected §  Muscle glycogen sparing has not been demonstrated in clinical studies

§  Exercise performance may not be improved –  Only 1 of 6 studies showed improvement from

immediate inges6on –  2 studies showed no improvement with chronic

inges6on

PROs CONs

Uncertainties

§  Effects on cardiac output and risk of cardiovascular disease §  Propor6on of lipid supplementa6on versus overall caloric intake §  Op6mal dura6on or schedule of supplementa6on

Further suppor6ve evidence from several well-‐designed studies would be required to recommend this approach for athletes

Dietary Supplements: Omega-‐3 (EPA and DHA)

43

Tar6bian B, et al. Clin J Sport Med. 2009;19:115-‐119; Huffman DM, et al. Eur J Appl Physiol. 2004;92:584-‐591; Mickleborough TD, et al. Chest. 2006;129:39-‐49; Mickleborough TD, et al. Am J Respir Crit Care Med. 2003;168:1181-‐1189; Tar6bian B, et al. J Sci Med Sport. 2010;13(2):281-‐286; Ernst E. J Intern Med Suppl. 1989;731:129-‐132; Smith GI, et al. Clin Sci (Lond). 2011;121(6):267-‐278. Panel on Macronutrients, Subcommi9ees on Upper Reference Levels of Nutrients and Interpreta6on and Uses of Dietary Reference Intakes, and the Standing Commi9ee on the Scien6fic Evalua6on of Dietary Reference Intakes. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fa9y Acids, Cholesterol, Protein, and Amino Acids (Macronutrients). The Na6onal Academies Press. 2005. Bloomer RJ, et al. Lipids Health Dis. 2009;19(8):36; Nieman DC, et al. Int J Sport Nutr Exerc Metab. 2009;19(5):536-‐546; Filaire E, et al. Int J Sport Nutr Exerc Metab. 2010;20(6):496-‐506.

§  May improve pulmonary func6on §  May decrease inflammatory mediators; reduce muscle soreness

§  May increase blood flow –  Op6mize oxygen supply and carbon

dioxide/lactate removal §  May promote anabolic response §  Improves 6me to fa6gue in recrea6onally-‐fit individuals

§  Suscep6ble to peroxida6on in 6ssues –  Leads to oxida6ve damage

§  Can reduce platelet aggrega6on –  Can increase bleeding 6mes, bruising, and

risk of hemorrhagic stroke §  Clinical trials have not shown a benefit in exercise performance or inflamma6on in healthy athletes –  Benefits in untrained individuals

PROs CONs

No recommended EPA:DHA intake

Further supportive evidence from several well-designed studies would be required to recommend this approach for athletes

Dietary Supplements: Conjugated Linoleic Acid

44 Khanal RC. Asian-‐Aust J Anim Sci. 2004;17(9):1315-‐1328. Lambert EV, et al. Br J Nutr. 2007;97(5):1001-‐1011; Kreider RB, et al. J Strength Cond Res. 200;16(3):325-‐334. Lowry LM. J Sport Sci Med. 2004;3:106-‐117.

§  May reduce body fat §  May improve lipid parameters §  May have an6-‐inflammatory effects

–  Enhance immune response §  May increase glucose u6liza6on §  May posi6vely affect bone modeling

§  Supplementa6on length is long for modest body composi6on benefits

§  No effect on body composi6on in regularly exercising individuals

§  In resistance-‐trained athletes, no effects on –  Total body mass –  Fat-‐free mass –  Percent body fat –  Bone mass –  Strength

PROs CONs

Uncertainties

§  Mechanisms of ac6on §  Species and dose influence results §  Specific isomer ra6o for op6mal effects §  Upper limit of safety

Further suppor6ve evidence from several well-‐designed studies would be required to recommend this approach for athletes

Lipids: Overall Summary §  Free fa9y acids from lipids provide the muscles with energy during longer, moderate exercise –  Triglycerides are the physiologic storage for these free fa9y acids

§  Lipids encompass many different compounds that can posi6vely or nega6vely affect health –  Abnormally high levels of lipid parameters are associated with an increased

risk of coronary heart disease

§ General dietary lipid guidelines can be used by athletes –  Intake needs are variable depending on exercise type, environmental

condi6ons, and availability of carbohydrate sources •  Endurance athletes may only need a total of 20% dietary fat •  Under cold condi6ons, an athlete may need up to 35% fat in dietary intake

§  Ergogenic lipid strategies for acute effects on exercise performance have not been encouraging –  Long-‐term suppor6ve effects on body composi6on and exercise recovery

are more promising 45

Appendix

Sources of Dietary Fat

Dietary Sources of Saturated Fat in the U.S.

47 Na6onal Cancer Ins6tute. Sources of saturated fat in the diets of the U.S. popula6on ages 2 years and older, NHANES 2005–2006. Risk Factor Monitoring and Methods. Cancer Control and Popula6on Sciences. h9p://riskfactor.cancer.gov/diet/foodsources/sat_fat/sf.html

aSpecific foods contribu6ng at least 1% of saturated fat in descending order: Cold cuts, yeast breads, salad dressing, pork and pork mixed dishes, soups, other white potatoes, reduced fat cheese, cream, quick breads.

Fats in Prepared Foods Calories Total fat, g Saturated fat, g Trans fat, g

French fries Ore-‐Ida Tater Tots, 1 serving 160 8 1.5 0

Ore-‐Ida Classic Golden Crinkle Fries, 1 serving 120 4.5 1 0

Arby’s, home-‐style (large) 610 26 3.5 0

Hardee’s (large) 470 21 4 Not reported

McDonald’s (large) 500 25 3.5 0

Wendy’s (large) 530 25 5 0

Burger King (medium) 410 18 3 0

Chicken and Fish Van de Kamp’s breaded fish s6cks, 6 260 13 2.5 Not reported

Burger King Tendercrisp chicken sandwich 750 45 8 0.5

Burger King big fish sandwich 640 32 5 0.5

McDonald’s chicken McNuggets, 10 470 30 5 0

Wendy’s Spicy chicken sandwich 520 22 6 0

Boston Market chicken pot pie, 1 800 48 24 0

KFC chicken pot pie, 1 790 45 37 0

KFC original chicken (breast, wing, and thigh) 730 45 11 0

Long John Silver’s ba9ered pollock, 1 260 16 4 4.5 48 Data from nutrition website at each company’s internet location; accessed January 18, 2012.

Fats in Baked Goods and Fros<ngs

49

Calories Total fat, g Saturated fat, g Trans fat, g Nabisco Nilla Wafers, 1 serving 140 6 1.5 0

Be9y Crocker Whipped Chocolate Fros6ng, 2 Tbs 100 4.5 1.5 1

Nabisco Oreos, 1 serving 160 7 2 0

Nabisco Chips Ahoy!, 1 serving 160 8 2.5 0

Pillsbury Creamy Supreme Vanilla Fros6ng, 2 Tbs 150 6 1.5 2

Entenmann’s apple snack pie, 1 430 24 13 0

Li9le Debbie’s Swiss Cake Rolls, 2 270 12 3 0

Entenmann’s chocolate fudge cake, 1/8 240 10 3.5 0

KFC biscuit, 1 180 8 6 0

Pillsbury Grands! bu9ermilk biscuit, 1 190 8 3 Not reported

Starbuck’s blueberry scone, 1 460 22 12 0.5

McDonald’s cinnamon melts, 1 460 19 9 0

Entenmann’s rich frosted donut, 1 300 20 13 0

Dunkin’ Donuts old fashioned cake donut, 1 320 22 10 0

Cinnabon classic cinnabon, 1 880 36 17 Not reported

Cheesecake Factory Linda’s fudge cake, 1 piece 1,370 Not reported 17 Not reported

Data from nutrition website at each company’s internet location; accessed January 18, 2012. .

Fats in Crackers and Snacks

50

Calories Total fat, g Saturated fat, g Trans fat, g Keebler Club original crackers, 4 70 3 0.5 0

Nabisco Ritz crackers, 1 serving 79 4 1 0

Nabisco Wheat Thins, 1 serving 140 5 1 0

Orville Redenbacher's natural microwave popcorn, 4 cups

110 8 2 2

Data from nutrition website at each company’s internet location; accessed January 18, 2012. .

Fats in Margarines

51

Calories Total fat, g Saturated fat, g Trans fat, g

Promise fat free, 1 Tbsp 5 0 0 0

Smart Beat Smart Squeeze, 1 Tbsp 5 0 0 0

Promise ac>v light, 1 Tbsp 45 5 1 0

Fleischmann’s olive oil, 1 Tbsp 60 6.5 1 0

Spectrum natural spread, 1 Tbsp 80 10 0.5 0

I Can’t Believe It’s Not Bu:er! light, 1 Tbsp 45 5 1.5 0

Shedd’s Spread Country Crock, 1 Tbsp 70 7 2 0

Promise s6ck, 1 Tbsp 80 9 2.5 0

Land O’Lakes Spread, 1 Tbsp 70 8 2 0

I Can’t Believe It’s Not Bu:er!, 1 Tbsp 70 8 2 0

Parkay, 1 Tbsp 80 9 1.5 1.5

Land O’Lakes s6ck, 1 Tbsp 100 11 2 2.5

Data from nutrition website at each company’s internet location; accessed January 18, 2012.

Fats in Bu>er and Dietary Fats

52

1 Tbsp Calories Total fat, g Saturated fat, g Trans fat, g Land O’Lakes light whipped 45 5 3 0

Land O’Lakes sweet cream whipped 50 6 3.5 0

Bu9er 85 10 6 0

Lard 115 13 5 0

Vegetable shortening 120 14 3 2

Chicken fat 115 13 4 0

Beef tallow 115 13 6 0

Data from WolframAlphaTM. Available at: http://www.wolframalpha.com. Land O Lakes data available at: http://www.landolakes.com/product/19416/salted-whipped-light-butter and http://www.landolakes.com/product/19406/salted-whipped-butter.

Sources of Omega-‐3 Fa>y Acids (1 of 3)

53

g/Tbsp

Olive oil 0.1 Walnuts, English 0.7 Soybean oil 0.9 Canola oil 1.3 Walnut oil 1.4 Flaxseeds 2.2 Flaxseed (linseed) oil 8.5

U.S. Department of Agriculture, Agricultural Research Service. 2011. USDA Na6onal Nutrient Database for Standard Reference, Release 24. Nutrient Data Laboratory Home Page, h9p://www.ars.usda.gov/ba/bhnrc/ndl

EPA + DHA g/g oil

Cod liver oil 0.19

Fish body oil 0.30

Omega-‐3, concentrate

0.50

Omacor 0.85

§  α-‐linolenic acid (vegetable omega-‐3)

§  Capsules


§  Fish §  Rough es6mates –  Oil content varies >300% by species, season, packaging, and cooking

54

EPA + DHA g/g oil Ounces providing ~1 g/day EPA + DHA

Tuna Light in water, drained White in water, drained Fresh

0.25 0.73

0.24 – 1.28

12 4

2.5 – 12.0

Sardines 0.98 – 1.70 2 – 3

Salmon Chum Sockeye Pink Chinook Atlan6c, farmed Atlan6c, wild

0.68 0.68 1.09 1.48

1.09 – 1.83 0.90 – 1.56

4.5 4.5 2.5 2.0

1.5 – 2.5 2.0 – 3.5

Mackerel 0.34 – 1.57 2.0 – 8.5

Herring Pacific Atlan6c

1.81 1.71

1.5 2.0

Trout, rainbow Farmed Wild

0.98 0.84

3.0 3.5

Halibut 0.40 – 1.00 3.0 – 7.5

Cod Pacific Atlan6c

0.13 0.24

23.0 12.5

Haddock 0.20 15.0

Ca�ish Farmed Wild

0.15 0.20

20.0 15.0

Flounder/Sole 0.42 7.0 U.S. Department of Agriculture, Agricultural Research Service. 2011. USDA Na6onal Nutrient Database for Standard Reference, Release 24. Nutrient Data Laboratory Home Page, h9p://www.ars.usda.gov/ba/bhnrc/ndl


§  Shellfish §  Rough es6mates –  Oil content varies >300% by species, season, packaging, and cooking

55

EPA + DHA g/g oil

Ounces providing ~1 g/day EPA + DHA

Oyster Pacific Eastern Farmed

1.17 0.47 0.37

2.5 6.5 8.0

Lobster 0.07 – 0.41 7.5 – 42.5

Crab, Alaskan king 0.35 8.5

Shrimp, mixed species 0.27 11.0

Clam 0.24 12.5

Scallops 0.17 17.5


Dietary Sources for Cholesterol (1 of 2)

§ Meat

56

3-‐oz serving mg/measure Beef Cuts (broiled, roasted, or braised) Ground (broiled) Liver (fried)

68 – 88 70 – 78 309

Chicken Cuts (fried or roasted) Liver (simmered)

71 – 87 479

Lamb Cuts (broiled, roasted, or braised)

74 – 93

Pork Cuts (broiled, roasted, braised, or

fried)

65 – 80

Turkey Cuts (roasted)

45 – 71


§ Dairy and Eggs mg/measure

Cheese Cheddar, 1 oz Co9age, 1 cup Cream, 1 Tbsp Feta, 1 oz Mozzarella, 1 oz Parmesan, 1 Tbsp Rico9a, 1 cup Swiss, 1 oz

30 36 16 25 22 4 125 26

Eggs, raw Medium Large Extra large

164 186 208

Milk, 1 cup Lowfat, 1% Reduced fat, 2% Whole, 3.25%

10 – 12 20 24

Dietary Sources for Cholesterol (2 of 2)

§  Fish

57

3-‐oz serving mg/measure Tuna Light in water, drained White in water, drained Fresh, cooked

26 36 40

Sardines 121

Salmon Sockeye, cooked Pink, canned Chinook, smoked

54 47 20

Herring Atlan6c, pickled

11

Trout, rainbow Wild, cooked

59

Halibut 51

Cod Pacific, cooked Atlan6c, cooked

48 47

Haddock, cooked 56

Ca�ish Channel, fried

60

Flounder/Sole, cooked 48

§  Shellfish

mg/measure

Oyster Eastern, 6 medium

22

Lobster, 3 oz 124

Crab, Alaskan king, 3 oz 45

Shrimp, mixed species, 3 oz canned

214

Clam, 3 oz 57

Scallops, 6 large fried 50


58

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