CARBOHYDRATES

LIPIDS

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CarbohydratesAldehyde or ketone compound with

multiple hydroxyl gpinclude sugars, starches, and fiber.

Provides energy store in our body[4 kcal/1gm]

Structural element of cell wall of bacteria/plant/arthropods

Linked to many protein n fat compound (Glycoprotein in membrane)

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MonosaccharideC6H12O6

Simple Carbohydrates

Glucose• mild sweet flavor• known as blood sugar• essential energy

source• found in every

disaccharide and polysaccharide

Fructose• sweetest sugar• found in fruits and

honey• added to soft drinks,

deserts

Galactose• hardly tastes sweet• rarely found naturally as a

single sugar

Simple Carbohydrates

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Maltose2 glucose units

• Germinating grains• Sweet potatoes• Dates• beer

Sucrose:– fruit, – vegetables,– grains

Lactose : glucose+galactosemain carbohydrate in milk 6

DISACCHARIDESpairs of the monosaccharide's

C12H24O12

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Complex Carbohydratesglycogen, starch, fiber

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Glycogen

• limited in meat and not found in plants– not an important dietary source of carbohydrate

• BUT– all glucose is stored as glycogen

• Long chain Must be broken down to be used by the body

Complex Carbohydrates

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Starches

• plant foods (potatoes, beans, peas, and grains such as rice corn and wheat).

• body hydrolyzes plant starch to glucose

Complex Carbohydrates

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Fiber

• Nor- starch polysaccharides– found in grains, fruits and vegetables

Complex Carbohydrates

Fiber types

• cellulose• pectins• lignins• Plant gums• mucillage

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Fiber

• Fiber: provides little energy and is indigestible.Absorbs water-increase bulk of stool & soften stool-promote bowel movements

- alleviate constipation- formation of gas & toxic substances-Keeps your digestive tract healthy.

• Inhibits mutagen in colon-CA colon

• CHD- binds to BS-cholesterol

• Gum/pectin-PPBS

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Carbohydrate Digestion• begins in mouth

– chewing releases saliva– enzyme salivary amylase hydrolyzes

starch to polysaccharides and maltose• stomach

– no enzymes available to break down starch

– acid does some breakdown– fibers in starch provide feeling of

fullness

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small intestine– majority of carbs digestion takes place here

– pancreatic amylase reduces carbs to glucose chains or disaccharides

– specific enzymes finish the job• maltase

– maltose into 2 glucose• sucrase

– sucrose into glucose and fructose• lactase

– lactose into glucose and galactose

Digestion

large intestine–1-4 hours for sugars and

starches to be digested–only fibers remain• attract water, which softens

stool–bacteria ferment some fibers• water, gas, short-chain fatty

acids (used for energy)

Digestion

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Carbohydrate Absorption

• glucose can be absorbed in the mouth• majority absorbed in small intestine

–active transport• glucose and galactose

–facilitated diffusion • fructose

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Maintaining Blood Glucose Homeostasis

IntestineWhen a person eats,blood glucose rises.

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Insulin stimulates the uptake of glucose into cells and storageas glycogen in the liver andmuscles. Insulin also stimulatesthe conversion of excessglucose into fat for storage.

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7 Blood glucose begins torise.

a The stress hormoneepinephrine and other hormonesalso bring glucose out of storage.

GlucoseInsulinGlucagonGlycogen

Glucagon stimulates livercells to break down glycogenand release glucose into theblood.a

Liver

Low blood glucose stimulatesthe pancreas to releaseglucagon into the bloodstream.

As the body's cells useglucose, blood levels decline.

Glucagon

Pancreas

Fat cell

Liver

Muscle

High blood glucose stimulatesthe pancreas to release insulin.

Pancreas

Insulin

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Imbalance

Diabetes: after food intake, blood glucose rises and is not regulated because insulin is inadequate

Hypoglycemia: blood glucose drops dramaticallytoo much insulin, activity, inadequate food intake, illness

Starvation- inadequate supply of carbohydrates- ketone bodies (fat fragments) are an alternate energy source-excess ketones can lead to ketosis

Lactose Intoleranceintestinal bacteria feed on undigested lactoseproduce acid and gas, lactose molecules attract water

cause floating, abdominal discomfort, diarrhea

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Glycemic Index

• way of classifying food according to their ability to raise blood glucose

• Rate and degree of blood sugar elevation following consumption

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Artificial Sweeteners

•Saccharin•Aspartame•Sucralose•Neotame

Diabetic pt.

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RDA45-65% of total energy intake

Daily Value is 300 grams per day

fiber intake: Daily Value 25-<40 gm

added sugar = <10% of energy

intake

FAT

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Fats are the body’s main form of long-term energy storage.

large molecules made up of FA and glycerol

Fatty acids are long chains of carbon atoms attached to hydrogen atoms.

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Simple lipids - TG

• major class of dietary lipid• in adipose tissue-coconut oil,

palm oil, cotton seed, butter, margarine

Compound lipid-

phospholipids

• minor portion of lipids in diet• lecithin is most common• important part of cell membranes

Derived lipid:- sterols

• Cholesterol• sex hormones, Vit D

Classification

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classificationSaturated fats

Lauric acidPalmateStearic acid

• No double bond C-C• solid at room temp • Animal origin—ghee,

butter, cheese, meat, fish..– obesity, high cholesterol

levels,increased risk of heart disease.

Unsaturated fats

double bond C=Cusually liquid at

room temperature.

Vegetable oil

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Unsaturated fats

MUFA Oleic acid

PUFA Lenolenic acid Lenoleic acid Arachidonic acid Eicosapentenoic acid

Safflower oil

Corn oil

Sunflower

Soybean

Groundnut

Mustard

Palm

Cod liver oil

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CORECHOLESTEROL

ESTERS

TRIGLYCERIDES

MONOLAYER OF PHOSPHOLIPID AND CHOLESTERLOL

INTEGRAL APOPROTEINS

PERIPHERAL APOPROTEINS

Structure of lipoprotein

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Class Source and functionMajor apoliproteins

Chylomicrons(CM)

Intestine. Transport of dietary TG to cell

A, B48, C(I,II,III) E

Very low density lipoproteins(VLDL)

Liver. Transport of endogenously synthesised TAG

B100, C(I,II,III) , E

Low density lipoproteins(LDL)

Formed in circulation by partial breakdown of IDL. Delivers cholesterol to peripheral tissues

B100

High density lipoproteins(HDL)

Liver. Removes “used” cholesterol from tissues and takes it to liver

A, C(I,II,III), D, E

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Trans FatAn unhealthy substance made through

the chemical process of partial hydrogenation of oils.

flavor & stability of foods

Deep fried fast foods, cake, chips….

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Is there reason for concern?

behave more like saturated fatty acids◦ More atherogenic◦ Takes many years to flush form body

Raises the LDL Lowers the HDL

making the arteries more rigid causing major clogs in the arteries◦ creating insulin resistance-

contribute to DM

significantly increase the chance of heart disease

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Hydrogenation

Vegetable oil vanaspati ghee

catalystLiquid semisolid form

keeping quality

Drastically EFA content

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Refined oilsRefining & deodorizing of raw oilTo remove free FA & rancid

materials

Quality & taste

costly

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Uses of FatEnergy- 9 kcal/gm

Insulation beneath skin

Support-Padding for organs

structural integrity of Cell membranes

Carry fat soluble vitamins

Precursor of Prostaglandin- vascular homeostasis

Make food more palatable

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Health Effects

Obesity

Phrenoderma-toad skin-due to deficiency

CHD »atherosclesis (cholestrol LDL)- >40%

energy supply form saturated fat

CA- colon/breast

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Choice of cooking oil

PUFA [safflower/sunflower/corn oil]

MUFA Ground-nut oil

Mustard oil

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Know Your Lipid Profile

Total Cholesterol < 200 mg/dl

LDL-Cholesterol < 100 mg/dl

HDL-Cholesterol ≥ 60 mg/dl

Triglycerides < 150 mg/dl

Fasting Blood Level Ideal, Healthy Level

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20-30 % of total energy intake • [The ICMR has recommended a daily intake of not

more than 20 % of total energy intake through fats]

>50% from vegetable oils

saturated fat <10%

trans fat <1%

Cholesterol <300 mg/Day

PUFA 6-10% of total energy intake

RDA

Thank you