Unit 6- Macronutrients - Lipids Flashcards
Types of Lipids X 5
1 • Triglycerides-_____+______
2 • Phospholipids-__________
fat and oil
lecithin
Types of Lipids X 5
3• ______ _________ - Vitamin A, carotenoids
4• ______ _________ - Cholesterol
5•_________ ____________– Lipoprotein, eicosanoids
Isoprene lipids
Steroid lipids
Lipid derivatives-
Types of Lipids
Usually possess one or more of the following:
1–Fatty acids
2—Isoprene
3—_____________
Cyclopentanoperhydrophenanthrene (CPPP)
Triglycerides
_____% of food lipids are TGs
Fat: mainly from animal sources, mainly SAFAs
Oil: mainly from plant sources, mainly PUFAs
Exceptions: plant oils with little PUFA
***Coconut oil —-High in medium-chain fatty acids
Olive oil—High in _____ ______ C18:1,9
90%
oleic acid
Phospholipids
The body’s reserve of PUFAs
Food sources: Soybean, egg yolk, wheat germ
__________– is a nutritional supplement to supply choline and PUFAs
Lecithin
Phosphatidylcholine = lecithin
USED FOR:
Memory loss. There is preliminary evidence that taking a single 25 mg dose of phosphatidylcholine (PC-55, TwinLab) can improve some measures of memory in healthy college students. Anxiety. Eczema. Gallbladder disease. Manic-depressive illness. Circulation disorders of the arms and legs. Weight loss. High cholesterol. Premenstrual syndrome (PMS). Alzheimer's disease. Depressed immunity. Preventing aging. Other conditions.
**More evidence is needed to rate the effectiveness of phosphatidylcholine for these uses.
The following doses have been studied in scientific research:
BY MOUTH:
For hepatitis C: 1.8 grams of lecithin, which contains phosphatidylcholine, used daily with a medication called interferon.
Phosphatidylcholine is a chemical contained in eggs, soybeans, mustard, sunflower, and other foods.
The term “phosphatidylcholine” is sometimes used interchangeably with “lecithin,” although the two are different. Choline is a component of phosphatidylcholine, which is a component of lecithin. Although closely related, these terms are not the same.
Because the body uses phosphatidylcholine to make a brain chemical called acetylcholine, there is some interest in using it for treating “brain-centered” conditions such as memory loss, Alzheimer’s disease, anxiety, manic-depressive disorders, and a movement disorder called tardive dyskinesia.
Phosphatidylcholine is also used for treating hepatitis, eczema, gallbladder disease, circulation problems, high cholesterol, and premenstrual syndrome (PMS); for improving the effectiveness of kidney dialysis; for boosting the immune system; and for preventing aging.
Phosphatidylethanolamine = cephalin
Phosphatidylethanolamines in food break down to form PE-linked Amadori products as a part of the Maillard reaction.[12] These products accelerate membrane lipid peroxidation, causing oxidative stress to cells that come in contact with them.[13] Oxidative stress is known to cause food deterioration and several diseases. Significant levels of Amadori-PE products have been found in a wide variety of foods such as chocolate, soybean milk, infant formula, and other processed foods. The levels of Amadori-PE products are higher in foods with high lipid and sugar concentrations that have high temperatures in processing.[12] Additional studies have found that Amadori-PE may play a role in vascular disease,[14] act as the mechanism by which diabetes can increase the incidence of cancer,[15] and potentially play a role in other diseases as well. Amadori-PE has a higher plasma concentration in diabetes patients than healthy people, indicating it may play a role in the development of the disease or be a product of the disease.[16]
Cephalin is found in all living cells, although in human physiology it is found particularly in nervous tissue such as the white matter of brain, nerves, neural tissue, and in spinal cord. Whereas lecithin is the principal phospholipid in animals, cephalin is the principal one in bacteria.
cephalin A group of phospholipid compounds, which includes phosphatidyl ethanolamine and phosphatidyl serine. Both are major phosphoglycerides in animals and higher plants, in which they are important constituents of membranes.
Phosphatidylinositol = lipositol
Phosphatidylinositol is an important lipid, both as a key membrane constituent and as a participant in essential metabolic processes in all plants and animals, both directly and via a number of metabolites. It is an acidic (anionic) phospholipid that in essence consists of a phosphatidic acid backbone, linked via the phosphate group to inositol (hexahydroxycyclohexane). I
Phosphoinositides and the inositol polyphosphates are key components of the nucleus of the cell, where they have many essential functions, including DNA repair, transcription regulation and RNA dynamics. It is believed that they may be activity switches for the nuclear complexes responsible for such processes, with the phosphorylation state of the inositol ring being of primary importance. Different isomers appear to have specific functions at each level of gene expression, so extracellular events must coordinate the production of these compounds in a highly synchronous manner.
The extraordinary range of activities of phosphoinositides is relevant to major human diseases, including cancer and diabetes, making them important targets for pharmacological research and intervention. It should also be noted that the phospholipase C isoenzymes regulate the concentration of phosphatidylinositol 4,5-bisphosphate and related lipids and thence their activities, in addition to the generation of new biologically active metabolites.
Phosphatidylserine
Phosphatidylserine is a chemical. The body can make phosphatidylserine, but gets most of what it needs from foods. Phosphatidylserine supplements were once made from cow brains, but now are commonly manufactured from cabbage or soy. The switch was triggered by a concern that products made from animal sources might cause infections such as mad cow disease.
Phosphatidylserine is used for Alzheimer’s disease, age-related decline in mental function, improving thinking skills in young people, attention deficit-hyperactivity disorder (ADHD), depression, preventing exercise-induced stress, and improving athletic performance.
How does it work?
Phosphatidylserine is an important chemical with widespread functions in the body. It is part of the cell structure and is key in the maintenance of cellular function, especially in the brain.
The following doses have been studied in scientific research:
BY MOUTH:
For Alzheimer’s disease, and other age-related thinking or memory impairment: 100 mg of phosphatidylserine three times daily.
Phosphatidylserine is POSSIBLY SAFE for most people. It’s been used in research studies for up to six months.
Phosphatidylserine use can, however, cause side effects including insomnia and stomach upset, particularly at doses over 300 mg.
There is some concern that products made from animal sources could transmit diseases, such as mad cow disease. To date, there aren’t any known cases of humans getting animal diseases from phosphatidylserine supplements, but look for supplements made from plants to be on the safe side.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Not enough is known about the use of phosphatidylserine during pregnancy and breast-feeding. Be on the safe side and avoid use.
Isoprenes
1—Isoprenoid lipids
2–Vitamin A (β-carotene, retinol)
3—Vitamin ___
4—Vitamin ___
E
K
Steroids
All steroids have __________
Cholesterol: most common steroid in foods
EX..In egg yolk, liver, red meat, shrimp and dairy
4-ring CPPP
Lipids –Fatty Acids
- Saturated (SAFA):–Primarily in animal fats
- ____________- Examples: palmitoleic and oleic
- ______________:-Primarily in vegetable oil
Mono-unsaturated (MUFA)
Poly-unsaturated (PUFA)
Essential fatty acids
omega-3 (Ω-3 or ω-3) and omega-6 (Ω-6 or ω-6)
– Only one substance in each of these families is truly
essential, because, for example, the body can convert
one ω-3 to another ω-3 but cannot create an ω-3
from scratch.
Linoleic acid (LA) = ω-6
α-Linolenic acid (ALA) = ω-3
KNOW
Essential fatty acids
In the body essential fatty acids serve multiple
functions
– They are modified to make the _________(affecting
inflammation and many other cellular functions); the
endogenous cannabinoids (affecting mood, behavior, and
inflammation);
the __________ from ω-6 EFAs and ________
from ω-3 (in the presence of aspirin, down-regulating
inflammation); the isofurans, isoprostanes, hepoxilins, epoxyeicosatrienoic acids, and neuroprotectin D; and the
lipid rafts (affecting cellular signaling)
eicosanoids
lipoxins
resolvins
Essential fatty acids
– They also act on ___________ _______ (activating or
inhibiting transcription factors for nuclear factor–κ-B
[NFκB], a proinflammatory cytokine)
• In each of these the balance between dietary ω-3 and ω-6 strongly affects _______
deoxyribonucleic acid
function
Essential fatty acids
Between 1930 and 1950 arachidonic and linolenic acids were termed essential because each was more or less able to meet the growth requirements of rats given fat-free diets
– Further research has shown that human metabolism requires both fatty acids
• To some extent any ω-3 and any ω-6 can relieve the worst symptoms of fatty acid deficiency
• However, in many people the ability to convert the ω-3 FA α-linolenic acid (ALA) to the ω-3 FA eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) is only _%efficient
– Therefore, it is important to incorporate the ___and ____ directly into the diet usually as fish or a fish oil supplement. Particular fatty acids such as DHA are needed at critical life stages (e.g., infancy and lactation) and in some disease states.
5
EPA
DHA
Important PUFAs
____________________–C18:2;9,12
In most vegetable oils: Sunflower, Safflower, evening primrose seed, Corn, Peanut, Canola, Olive
Converted to:
1–γ-linolenic acid (GLA) C18:3;6,9,12
Small amounts in diet: In borage seed, evening primrose, and black currant oils, human milk
2—Dihomo- γ-linolenic acid (DGLA) C20:3;8,11,14
3–___________ __________-
Abundant in peanut, egg yolk, fish and meat
LA: very abundant – no supplement necessary
AA: Made de novo & abundant – no
supplement necessary
Linoleic acid (LA)
-Arachadonic acid C20:4;5,8,11,14
Important PUFAs
EX. α-Linolenic acid (ALA) C18:3;9,12,15
Converted in the human body to
1– Eicosapentaenoic acid (____) C20:5;5,8,11,14,17
2—Docosahexaenoic acid (_____) C22:6;4,7,10,13,16,19
A—– Found in fish oil and fish oil supplements
EPA
DHA
Essential Fatty Acids & Disease
• _______ __________: high EFA in diet helps prevent
hypertension. The AHA recommends 2 servings
(2-3 oz/serving) of fatty fish per week. FDA allows a qualified claim on the reduction of risk of coronary heart disease by ω-3 FA.
•_______ _________- RA patients deficient in γ-LA,
responded well to supplements, with reduction in
morning stiffness, joint swelling, tenderness and pain.
• Skin conditions: EFAs may prevent dry, itchy and
inflamed skin. Deficiency in γ-LA has been associated
with ________. Taking γ-LA supple
Heart disease
eczema
Digestion, Absorption & Transport
______ _________– digests short & medium-chain FA
Lingual lipase
Digestion, Absorption & Transport
_______ _____________= digests < 30% dietary TGs
Gastric lipase
Digestion, Absorption & Transport
________ _________ digests TGs emulsified by bile salts
Pancreatic lipase
TGs»_space;>Free Fatty Acids + 2-monoacylglycerol + glycerol
Phospholipids———–>Free Fatty Acids + lysophospholipids
ENZYME = _____________
Cholesterol esters———> Free Fatty Acids + cholesterol
ENYME = ____________
Phospholipase A2
Cholesteryl esterase
Daily Requirements
Daily ω-6 and ω-3 recommendations at a 2:1 to 3:1 ratio
(vs. ______ or more in the current American diet)
The Institute of Medicine has established Adequate Intakes for ALA (1.1-1.6 g/day) and LA (11-17 g/day) for adults
16:1
Digestion
1—Within mucosal cells, the digested components are
Reassembled to esters “__________________”
Covered with apolipoproteins to form___________ for
transport
2—Short-chain (C4-C8) and medium-chain (C10-C14) FAs are transported directly (not re-esterified or chylomicronized)
A fat substitute for patients who cannot digest fats
(e.g. ____________)
re-esterification
chylomicrons
steatorrhea)
Transport
Lipoproteins for lipid transport HDL: mostly made in liver (some in small intestine), for scavenging _____ ________. Free cholesterol is esterified to cholesteryl ester by Lecithin-Cholesterol Acyl Transferase (L-CAT)
The cholesteryl ester is transported by HDL, eventually returned to ______ for metabolism.
free cholesterol
liver
Fate of fatty acids in the liver
β-oxidation yields ATP (reduced need for TCA)
Why make ketone bodies? More easily metabolized than FA by many tissues… reducing need for gluconeogenesis… sparing ___________
protein
Hormones that Regulate Triglyceride storage and mobilzation
1—INSULIN: Increases _________ by increasing
- -Glycolysis
- –Activity of Acetyl-CoA carboxylase
- —Production of NADPH
- –Activity of HMG-CoA reductase
***Increases lipogenesis by __________
Hormone-sensitive lipase activity (blocks lipolysis) by dephosphorylation
lipogenesis
decreasing
Hormones that Regulate Triglyceride storage and mobilzation
2 & 3 • EPINEPHRINE and GLUCAGON:
—Increase lipolysis by _________
Glycolysis (via PFK-1 & PK activity in liver/ms)
—-Reduces _________supply for lipogenesis —-Activity of Acetyl-CoA carboxylase (blocks lipogenesis)
—-Increase lipolysis By INCREASING
cAMP, decreasing ____________
(blocking cholesterol synthesis)
…All by phosphorylation cascades
DECREASING
acetyl-CoA
N/a
10 Major Functions of Lipids
- Energy
- Structure
- Insulation
- 2nd messengers
- Cholesterol
- Steroid hormones (from cholesterol)
- Vitamin D
- Bile acids
- Synthesis of Eicosanoids
- Relationships to cancer
Know
10 Major Functions of Lipids
- Energy—-Under aerobic conditions, FA undergo _________—->Krebs—->ETC—->ATP
- Structure—-PL are essential for cell membrane. ______ makes cell membrane more fluid
- Insulation
Subcutaneous fat protects vs. loss of body heat. Fat between visceral organs serves as a cushion and prevents ________
β-oxidation
Cholesterol
friction
10 Major Functions of Lipids
- _______ messengers
Phosphatidyl inositolPI-4,5-bisphosphate - Cholesterol–Synthesized from __________
Enhanced by SAFA - _________ synthesis —(made from cholesterol) Adrenocorticoids: Glucocorticoids, mineralocorticoids Sex hormones: estrogens, testosterone, progesterone.
Second
acetyl-CoA
Steroid
10 Major Functions of Lipids
- Vitamin D–From _________
- Bile acids: from cholesterol Emulsifiers for ______ digestion
- Synthesis of ________: (from C20 PUFAs)
cholesterol
lipid
Eicosanoids
9—Eicosanoids
Most are produced from _____ ________, a 20-carbon polyunsaturated fatty acid (C20:4;5,8,11,14- eicosatetraenoic acid).
The eicosanoids are considered “__________ _________”
They have specific effects on target cells close to their site of formation.
They are rapidly degraded, so they are not transported to distal sites within the body.
But in addition to participating in _________ signaling, there is evidence for involvement of eicosanoids in _________ signal cascades.
arachidonic acid
local hormones.
intercellular
intracellular
10 Major Functions of Lipids
- Synthesis of Eicosanoids: (from C20 PUFAs)
Arachidonic Acid= ω-6 eicosanoids = _________
Eicosapentaenoic Acid (EPA) =. ω-3 eicosanoids = _________
Enzymes
COX-1–Constitutively expressed (kidney, GI, platelets)
COX-2–Inducible by cytokines & TNF-α
COX-3 Phospholipase A2
5-lipoxygenase
Inflammatory
ANTI-inflammatory
10 Major Functions of Lipids
- Relationships to cancer
Animal ________ cancer: chemically induced, enhanced by fat/oil, mostly ω-6 PUFA, SAFA
Animal _______ cancer: INCREASED by ω-6, REDUCED by ω- 3, possibly CLA.
Animal _____ cancer: increased by ω-6 or total kcal, reduced by ω-3 or aspirin
pancreatic
mammary
colon
*****Human breast cancer: may be reduced by ω-3 and possibly MUFA. May be increased with ω-6 or trans-fatty acid (Cancer tissue has higher ω-6 levels)
Human colon cancer: positively correlated with red meat and low dietary fiber.
Daily Requirements of FATS • DRI (RDA/AI)
• Infants 0-6 mo.—31 grams RDA
• Infants 7-12 mo. –30 grams RDA
• Everyone else:— No RDA or AI
Know
Deficiency
• Deficiency is rare (obviously)
– Most deficiencies are with essential fatty acids
• Rats lacking EFA:
– Retarded growth, scaly skin, tail necrosis, kidney lesions, hematuria, high mortality rates of offspring
Know
Deficiency
• Humans lacking EFA:
– Dermatitis and delayed _____ _____
• Could impair absorption of fat-soluble vitamins
• Cholesterol: made de novo; but epidemiological studies suggest low [blood] associated w/ cancer
wound healing
Excess fat
1–• Average diet supplies ~40% kcal as fat
2–• Lipids are energy-dense
Therefore small increases—->obesity. About 90-95% overfed lipids stored as fat
3–• Too much fat intake impairs _______ function Fat intake breast cancer ?? Adipose—>synthesize estrogen—>cancer
immune
How low can you go?
1–• The Pritikin diet has ~____-____% lipid.
2–• Fat substitutes
3–• Simplesse (protein microparticles-4kcal/g)
4–• Olestra (sucrose ester) – no calories (not digested)
5—.• Blood-clotting studies indicate that absorption of vitamin K is not likely affected
6–• Add bulk and softening of stool
10-15
10 simple rules to Pritikin diet
- Start each meal with soup, salad, fruit, or whole grains. They fill you up, so you’re less likely to eat high-fat, high-calorie food.
- No more high-calorie drinks, especially soda. A daily glass of wine can be good for the heart, but skip most alcoholic beverages.
- Avoid high-calorie foods.
- Snack at set times and only on healthy foods.
- Choose whole, unprocessed foods as often as possible, and always avoid fast food.
- Exercise regularly, combining lots of walking with strength training
- Go easy on meat, especially red meat. Instead, opt for fatty fish like salmon.
- Skip extra salt.
- Don’t smoke.
- Ease stress.
Know
Pritikin diet details
• The overall diet is low in fat and high in fiber. The recommended foods are fruits, vegetables, low-fat dairy, lean protein, and fish.
Items to minimize include oils, refined sugars, salt, and refined grains. The plan recommends avoiding processed meats, foods high in saturated fat and those made with trans fat, and high-cholesterol foods like eggs.
- –High in cholesterol; may increase risk of CVD, colon and breast cancer, and gallstones
- – High levels of SAFA, especially _____ is found to increase cholesterol
C16
Trans-Fatty Acids
• Trans versus cis format
• Sources of trans-fatty acids =
—Partially hydrogenated margarine, shortening, commercial frying fat, high-fat _____ goods, _______ snacks
baked
salty
