Dr. Shailendra Meena presents information on lipids and fats. Key points include:
- Fats are insoluble in water and function to provide insulation, energy storage, and carry fat-soluble vitamins. Most body fat is stored in adipose tissue.
- Dietary fats are composed of fatty acids, triglycerides, phospholipids, and cholesterol. Fat molecules contain one alcohol and three fatty acids.
- Fats provide energy, insulation, and carry fat-soluble vitamins. They also aid nutrient absorption and provide a sense of fullness.
- Sources of dietary fats include animal foods like butter and plant oils. Fats are classified based on biochemical composition and nutritional significance
2. Introduction
Fats are best known members of a chemical group
called the lipids.
The term lipid is applied to a group of naturally
occurring substances characterized by their
insolubility in water, greasy feel and solubility in
organic solvents like ether, chloroform, benzene or
other fat solvents.
The term lipid was first used by the German
biochemist Bloor in 1943
3. Introduction cont….
In normal human subjects, fats constitutes between
10-15 % of body weight.
Most of the body fat(99%) is stored in the adipose
tissues.
Fat present in the diet or in human body are in the
form of fatty acids, triglycerides, phospholipids and
cholesterol.
Each fat molecule is made up of four compounds, one
alcohol and three fatty acids.
6. Functions of Fats
1) Insulation and Padding:
Fats are deposited in adipose tissue, subcutaneous tissue
and abdominal cavity
Fats surrounds the organs and laced throughout muscle
tissue
Fats functions like insulating material against cold
Fats protects vital organs against physical injuries by
forming a padding around them
7. Functions of Fats cont…
2. Energy:
The primary function of fat is to supply energy.
It is a very concentrated source of energy.
Each gram of fat when oxidized yields approximately 9
kcal, twice as much energy as one gram of carbohydrate or
protein.
Fat specially supply energy in between the meals and
during starvation.
8. Functions of Fats cont…
3. Carriers of fat soluble vitamins:
Dietary fat is a carrier of the fat soluble vitamins-A,D,E
and Vitamin K
Fat is also necessary for the absorption of Vitamin A and
its precursor, carotene.
9. Functions of Fats cont…
4. Satiety function:
Fats improves the palatability of the diet.
It slows digestion--resulting in satiety (a sense of
fullness and satisfaction after eating).
In the absence of fats the food become non palatable.
10. Functions of Fats cont…
5. Fats provide essential fatty acids which the
body can’t manufacture.
6. Fats are the constituents of cell membrane
and regulates the membrane permeability.
7. Fats are also function as cellular metabolic
regulators in the form of prostaglandins and
steroid hormones.
11. Sources of dietary FATS
Fats of animal origin : Ghee, butter, milk, cheese, eggs
and fat of meat and fish
Fats of plants origin: Groundnut oil, Coconut oil,
Palm oil, Mustard oil, Canola
oil, Sesame oil, Corn oil
Other Sources: Cereals, Pulses, Oil seeds (Sunflower,
Safflower, Soyabean, Cottonseeds), rice
bran and Leafy green vegetables
12. Classification of Fats
Mainly classified into two ways:
A) Based on bio chemical composition
B) Based on nutritional significance
13. Bio chemical classification of fats
A. Simple Lipids:
Simple lipids are defined as those which yield only
one or more fatty acids and an alcohol on hydrolysis.
Example: 1) Fats and Oils, also known as triglycerides
2) Waxes
14. Bio chemical classification of fats cont….
B. Compound Lipids:
Compounds lipids are those lipids which contain in
addition to fatty acids and glycerol, some other organic
compounds such as phosphoric acid, nitrogenous
base, sugars and Proteins.
Example:
Phospholipids, Sphingolipids, Glycolipids,
Sulpholipids and lipoproteins
15. Bio chemical classification of fats cont….
C. Derived Lipids:
These are the derivatives obtained on the hydrolysis
of simple and compound lipids which possess the
characteristics of lipids.
Example:
Fatty acids, mono and diacylglycerols, lipid soluble
vitamins, steroid hormones and ketone bodies
17. Digestion of Fats
Five different phases:
Hydrolysis of triglycerides (TG) to free fatty acids (FFA)
and monoacylglycerols
Solubilization of FFA and monoacylglycerols by
detergents (bile acids) and transportation from the
intestinal lumen toward the cell surface
Uptake of FFA and monoacylglycerols into the cell and
resynthesis to triglyceride
Packaging of TG’s into chylomicrons
Exocytosis of chylomicrons into lymph
18. Enzymes Involved in Digestion of Lipids
lingual lipase: Hydrolyze short and medium chain
fatty acids.
Gastric Lipase: Hydrolyze Long, medium and short
chain fatty acids.
Pancreatic lipase: major enzyme affecting
triglyceride hydrolysis
Colipase: protein anchoring lipase to the lipid
lipid esterase: secreted by pancreas, acts on
cholestrol esters, activated by bile
phospholipases: cleave phospholipids, activated
by trypsin
25. Saturated fatty acids continues..
Saturated fats are considered as harmful fats
because they increases total cholesterol level and
TGs level.
Sources :
Animal foods such as meat, poultry and full-fat
dairy products
Tropical oils such as palm and coconut
RDA: Less than 10% of total energy intake per day.
26. Unsaturated fatty acids
Fatty acid with one or more points of Unsaturation.
Unsaturated fats are found in foods from both plant and
animal sources.
27. Monounsaturated fatty acids
Fatty acid containing one point of Unsaturation.
They are considered as beneficial for human health.
Replacing SFA with MUFA reduces LDL cholesterol
concentration and total cholesterol / HDL cholesterol
ratio.
Replacing carbohydrate with MUFAs increases HDL
cholesterol concentration.
Sources: vegetable oils such as olive, canola, and peanut.
RDA: By difference
29. Cis- unsaturated fatty acids
Natural unsaturated fatty acids have Cis- double bonds.
The unsaturated fatty acids can’t bunch tightly together.
The bend helps the fat stay liquid rather than solid.
Significance –
Decreases total cholesterol and TGs level.
Increases HDL level.
30. Trans unsaturated fatty acids
Unsaturated fatty acids (MUFAs and PUFAs) containing
one or more double bonds in trans configuration are called
trans fatty acids (TFAs).
Hydrogen atoms are on the opposite sides of the molecule.
31. Trans fatty acids cont….
Produced during partial hydrogenation of vegetable oils.
Partially hydrogenation of vegetable oil results in longer
shelf life of a product. less rancidity and oxidation when
exposed to heat and light.
Also developed in vegetable oils during frying and heating.
Sources:
“Formation of trans fatty acids in edible oils during the frying and heating
process” (Vol.123, No.4, 15Dec.2010, pp 976-982, doi:
10.1016/j.foodchem.2010.05.048)
32. Why trans fatty acids are harmful …
Trans fatty acids are much more linear than cis fatty acids,
so their melting points are higher and studies have shown
that trans fats may act similarly to saturated fats.
Increases the ratio of total cholesterol to HDL cholesterol,
a powerful predictor of the risk of CHD
A recent study suggests trans fats harm the cardiovascular
system by triggering inflammation in blood vessels.
In addition, trans fat may increase risk for cancers of the
breast and prostate.
33. Trans fatty acids cont….
Sources:
1. Spreads: Butter, margarine
2. Package foods: Cake mixes, Biscuits
3. Soups: Plain soups, Noodle soups
4. Fast foods: Deep fried Fish and Chicken, Pancakes
5. Frozen foods: Frozen pies, pot pies, wafers
6. Backed foods: Cakes, doughnuts
7. Chips and Crackers: Potato chips
8. Cookies and Candy: Choc0late bars, Cream filled
cookies
34. RDA for Trans fatty acid
The American Heart Association recommends limiting
total trans fat intake to less than 1 percent of our total daily
calories, which means less than 2 grams per day for many
people.
Since most of us get that much from naturally occurring
trans fat in red meat and dairy, we need to cut trans fat
from other foods to zero.
That means checking every ingredient list and bypassing
foods that declare any hydrogenated oils or partially
hydrogenated oils, even if it states "trans fat 0 g" on the
nutrition panel.
35. Polyunsaturated fatty acids
Polyunsaturated fatty acids are those fatty acids where
Unsaturation occur more than two points.
They possess protective role on human health. considered as
beneficial for consumption.
36. Polyunsaturated fatty acids cont…
Increase esterification process of cholesterol & prevents its
absorption.
By increasing the synthesis of eicosanoids, acts as an anti
platelet aggregating factor, so decreases the chances of clot
formation.
Decreases the synthesis of the precursor of VLDL AND TGs.
Increases clearance of LDL cholesterol.
37. Polyunsaturated fatty acids cont…
Sources:
Found in nuts and vegetable oils such as safflower,
sunflower, and soybean, and in fatty fish.
RDA: 6-10% of total energy intake per day.
38. Essential Fatty Acids:
There are two PUFAs which cannot be synthesized in
the body and required in the preformed state in diet
for growth and maintenance of normal skin.
These are called Essential fatty acids and include
linoleic acid and linolenic acid.
The term essential fatty acid was introduced by Burr
and Burr.
39. Essential Fatty Acids cont…..
Sources of linoleic acid:
Leafy vegetables, nuts, vegetable oils (seasame, corn oil,
sunflower, soybean), poultry fat
Sources o f linolenic acid:
Nuts, seeds (soybean, walnuts, flaxseed) and oils
(soybean, canola)
RDA: Minimum intake levels for essential fatty acids
estimated to be 2.5% E LA and 0.5% E ALA
40. Omega 6 Fatty Acid- Linoleic acid
RDA: 5-8% of total energy intake per day
Sources:
Safflower oil
Sunflower oil
Corn oil
Soybean oil
Pros:
- helps lower LDL cholesterol; thereby lowering our risk of
heart disease
- helps make our blood "sticky" so it is able to clot
- support skin health
41. Omega 6 Fatty Acid (continued)
But when omega-6s aren't balanced with sufficient amounts of
omega-3s…
Cons:
- Excessive amounts increase the inflammatory response in
our bodies
- Can exacerbate conditions like arthritis, lupus and perhaps
some cancers
- When blood is too 'sticky,' it promotes clot formation―
increasing the risk of heart attack and stroke
42. Omega 3 Family of Fatty Acids
ALA (alpha linolenic acid)
RDA: 1-2 % of total energy
intake per day
Sources:
Flaxseed
Walnuts
Canola oil
Soybean oil
Dark green vegetables
(Mint,Watercress,Parsley)
43. Omega 3 Family of Fatty Acids (continued)
ALA can convert to other omega 3 fatty acids—DHA and
EPA (at a very low percentage)
DHA = Docosahexaenoic acid
EPA = Eicosapentaenoic acid
Sources:
Fish
Mother’s milk
44. Specific Functions of Each
DHA:
- important for maintaining neurotransmitter function and a
calming effect on the nervous system
- anti-inflammatory effect in the joints, blood stream and
tissues
- support retinal and brain development in fetus and infants
EPA:
- fights inflammation by bolstering the immune system
- prevents clotting thus helping to prevent cardiovascular
events
- prevents some heart arrhythmias
45. Health Benefits of Omega 3 Fatty acids
Reduces the risk of coronary heart disease:
-
Stimulates blood circulation
Increases the breakdown of fibrin-thus lowering the clot
formation
Lower triglycerides
Acts as an anti-inflammatory agent
Lowers blood pressures (a little)
Promotes nervous system’s health and development
46. 2.Triglycerides
Structure
Glycerol + 3 fatty acids
Functions
Energy source
9 kcals per gram
Form of stored energy in adipose tissue
Insulation and protection
Carrier of fat-soluble vitamins
Sensory properties in food
47. 3.Phospholipids
Structure
Glycerol + 2 fatty acids + phosphate group
Functions
Component of cell membranes
Provides lipid transport, as part of lipoproteins
Emulsifiers
Food Sources: Most abundant in egg yolks, liver,
soybeans, and peanuts
48. 4.Sterols: Cholesterol
Functions
Component of cell membranes
Precursor to other substances
Sterol hormones
Vitamin D
Bile acids
Synthesis
Made mainly in the liver
Food Sources: Highest in organ meats like beef
kidney, beef liver, and beef brain, egg yolks, and
breast milk
49. Total Cholesterol
Direct, positive association between TC and CHD
risk
Diets high in saturated fats raise total cholesterol
and CHD incidence and mortality
ATP-III Guidelines: lowering total cholesterol and
LDL-C reduces CHD risk
10% reduction in TC decreases CHD risk by about
30%
50. 5.Eicosanoids
These compounds are derived from long chain poly
unsaturated fatty acids
Prostaglandins.
They have roles in:
Prostacyclines,
Inflammation
Fever
Regulation of blood pressure
Blood viscosity
Blood clotting
Tissue growth
Bronchocostriction
Asthma.
Thromboxanes
Leukotrienes
51. 6.Lipoproteins
Lipoproteins serve as a transport vehicle for lipids in
the blood and lymph
Major classes
Chylomicrons
VLDL
LDL
HDL
53. Chylomicrons
Largest particles
Transport dietary fat and cholesterol from the small
intestine to the liver
In the bloodstream, triglycerides are hydrolyzed by
lipoprotein lipase (LPL) in muscle and adipose tissue
When 90% of triglyceride is hydrolyzed, released into
blood as a remnant
Liver metabolizes remnants, but some deliver cholesterol
to the arterial wall
54. VLDL:- rich in CE and TGsSurface
Monolayer
Phospholipids
(12%)
Free Cholesterol
(14%)
Protein (4%)
Transport
endogenous
cholesterol
Hydrophobic Core
Triglyceride (65%)
Cholesterol Esters
(8%)
55. Very-Low-Density-Lipoproteins
Manufactured in the liver to transport
endogenous triglyceride and cholesterol
60% is triglyceride
Large VLDL may be non atherogenic
VLDL remnants or IDL appear to be atherogenic
Not routinely measured, but TG in them is
measured in total triglyceride
56. LDL:- cholesterol rich.
Surface Monolayer
Phospholipids
(25%)
Free Cholesterol
(15%)
Protein (22%)
Synthesized
from VLDL in
blood
circulation.
Transports
cholesterol from
liver and delivers
to other tissues.
57. Intermediate-Density Lipoprotein
Formed with catabolism of VLDL, a precursor of LDL
Rich in cholesterol and apo E
High concentrations of IDL and VLDL remnants
directly related to lesion progression and coronary
events
Not routinely measured, though components can be
58. Low-Density Lipoprotein
Primary cholesterol carrier in blood
Total cholesterol and LDL-cholesterol are strongly correlat
LDL is formed in VLDL catabolism, 60% is taken up by LDL
receptors in liver, adrenals, other tissues; rest is metabolized
via alternative pathways
Number and activity of receptors determines LDL
cholesterol levels in the blood
59. LDL-Cholesterol
Particles heterogeneous in size, density, lipid
components
Phenotype A: large particles, not associated with
disease risk
Phenotype B typified by small, dense LDL particles;
triglyceride rich, cholesterol depleted; predictive of
CHD risk in men and women
60. High density lipoproteinSurface Monolayer
Phospholipids (25%)
Free Cholesterol (7%)
Protein (45%)
Promotes reesterification process
of cholesterol.
Reverse cholesterol
transport
61. High Density Lipoproteins (HDL)
Contain more protein than the other
lipoproteins
Apo A-1 is involved in tissue
cholesterol removal
High HDL is associated with low
levels of Chylomicrons, VLDL
remnants, and small, dense LDL
65. 1.Cardiovascular disease
The Prevalence of Coronary Heart Disease (CHD)
“ HEART ATTACK” is rapidly increasing in India
It has become an “ EPIDEMIC”.
It is a major contributor for mortality and
morbidity.
66. Cardiovascular disease cont…
Cardiovascular disease will account for 33.5% of
total deaths by the year 2015, would replace
infectious diseases, as the number one killer in the
Indian Population.
It is expected that deaths due to HEART ATTACK
will double in the next 10 years
The death rate due to heart attack will be 295 per
1,00,000 population in the year 2015.
67. Unchangeable Risk Factors
Age- the older you get, the greater the chance.
Sex- males have a greater rate even after women pass
menopause.
Family history- if family members have had CHD,
there is a greater chance.
Personal Medical History- other diseases such as
Diabetes Mellitus can increase chances.
69. Primary Prevention of CHD
Know your risk factors
Make dietary changes
Start/continue exercise
Stop smoking
Stress reduction
Use medication if necessary
70. Risk Factors for CHD cont..
High Total Blood Cholesterol
>200 mg/dl: borderline high risk
>240 mg/dl: high risk
High LDL-C
>130 mg/dl: borderline high
>160 mg/dl: high risk
73. Risk Factors for CHD cont..
Low HDL-C
< 40mg/dl : high risk
> 60mg/dl : protective
74. Increasing your HDL-C
Aerobic exercise for 30 min a day
Loosing weight
Restrict trans fats in the diet
By taking diet rich in whole grains, Nuts,
legumes, fruits, vegetables and fish
75. 2.Obesity
It is defined as abnormal increase in the body weight
due to excessive fat deposition
Obesity is a state of excess adipose tissue mass
Man & Women are consider obese if their weight due
to fat (in adipose tissue) respectively, exceeds more
than 20% and 25% of body weight.
76. Nutritional basis for Obesity
Obesity is basically a disorder of excess calorie intake, in
simple language –overeating.
Every 7 calorie of excess consumption leads to 1 gm fat
deposit and increase in bodyweight.
Over eating coupled with lack of physical exercise
further contribute to obesity.
77. Indices for Obesity measurement clinicaly
A) Body Mass Index-BMI
Clinicaly obesity is represented by BMI
BMI is calculated as the weight in kg divided by the
Height in meter square
78. Body mass index cont……
Classification of weight status and risk of disease
Category
Obesity Class
Risk of disease
< 18.5
Nil
---------
18.5 to 24.9
Nil
---------
Over weight
25 to 29.9
Nil
Increased
Obesity
30 to 34.9
Class I obesity
High
Obesity
35 to 39.9
Class II obesity
Very high
Extreme Obesity
40 or >40
Class III obesity
Extremely high
Under weight
Healthy weight
BMI (Kg/M sq.)
79. Indices for Obesity measurement clinicaly cont…
B) Ratio between waist and hip size:The distribution of adipose tissue in different anatomic
depots has substandard implication for morbidity.
Intra abdominal and abdominal subcutaneous fat have
more significance than subcutaneous fat present in the
buttocks and lower extremities
80. Indices for Obesity measurement clinicaly cont…
This distribution is measured clinically by determining
the waist to hip ratio.
With a ratio More than 0.9 in women and more than
1.0 in Men is considered abnormal.
Many of the most important complication of obesity ,
such as insulin resistance, diabetes, hypertension and
hyperlipidemia are linked more strongly to intra
abdominal and/or upper body fat than over all
adiposity.
81. Genetical aspect of obesity
One gene namely Ob gene, expressed in adipocytes (of
white adipose tissues) producing a protein called
leptin is closely associated with obesity.
Leptin is regarded as body weight regulatory
hormone.
It binds to a specific receptor in brain and function as
a lipostat.
82. Genetical aspect of obesity cont…
When the fat store in the adipose tissue are adequate,
leptin levels are high.
This signals to restrict the feeding behaviour and limit
fat deposition.
Any genetic defect in leptin or its receptor will lead to
extreme overeating and massive Obesity.
83. Pathologic consequences of obesity
Obesity is associated with an increase in mortality ,
with a 50-100% increased risk of death from all causes
compared to normal weight individuals, mostly due to
cardiovascular causes.
Life expectancy of a moderately obese individual
could be shorted by 2 to 5 years.
A 20 to 30 year old male with a BMI >45 may lose 13
years of life.
84. Pathologic consequences of obesity cont..
Obesity causes insulin resistance which leads to type 2
DM
Obesity causes cardiovascular diseases:“ The Framingham study revealed that obesity was an
independent risk factor for the 26 year incidence of
cardiovascular diseases in man and women.”
85. Diet therapy for obesity
The primary focus of diet therapy is to reduce overall
calorie consumption
The NHLBI recommended initiating treatment with a
calorie deficit of 500-1000 Kcal/day compared to
patients habitual diet.
This reduction is consist with a goal of loosing
approximately 1-2 Ib per week.
86. Diet therapy for obesity cont..
This calorie deficit can be accomplished by suggesting
substitutions or alternatives to diet.
Example:Choosing small portion sizes of meal
Eating more fruit and vegetables
Consuming more whole grain cereals
Selecting skimmed dairy products
Reducing fried foods and other added fats and oils
Drinking water instead of calorie beverages
87. Recommendations for dietary Fats
(FAO/WHO expert consultation on fats in human nutrition, Geneva,2008)
Recommendations for dietary fats are directed
towards: Meeting the requirement of optimal foetal and infant
growth and development
Maternal health
For combating chronic energy deficiency in children
and adults
Diet related non-communicable diseases in adults
88. Recommendations for dietary Fat intake for Indians (ICMR-2010)
Age/Gender/Ph
ysiological
groups
Physical
activity
Adult Man
Sedentary
Moderate
Heavy
Adult Women
Minimum level
of Total fat
(%E)
20
Fats from foods
other than visible
fats (%E)
10
Visible Fat
(%E)
gm/day
10
25
30
40
20
10
10
25
30
40
Pregnant
20
10
10
30
Lactating
Infants
Sedentary
Moderate
Heavy
20
10
10
30
0-6 months
07-24 months
Children
10-12 years
13-15 years
16-17 years
Girls
10-12 years
13-15 years
35
Fat present in Human Milk
10
25
3-6 years
7-9 years
Boys
40-60
25
25
30
25
10
15
35
45
50
35
40
89. Recommendations for visible fats
The quantity and fatty acid composition of both visible fat
and fat from all other foods (invisible fats) contribute to
the intake of various fatty acids in the total diet.
The data on fatty acid intake in Indian adults determined
by taking into account the contribution of various fatty
acids from all foods (invisible fat) & visible fats ( in diets of
either rural or urban population respectively) shows that a
complete dependence on just one vegetable oil does not
ensure the recommended intake of fatty acids for optimal
health and prevention of DR-NCD
90. Recommendations for visible fats cont..
A long term(in home) study with oil combinations
(which increase ALA) showed improvement of LC n-3
PUFA nutritional status in adults
Therefore, to ensure optimal fat quality, the use of
correct combination of vegetable oils is recommended
91. Recommendations for visible fats cont..
1) Use correct combination / blend of 2 or more vegetable
oils (1:1)
(a) Oil containing LA + oil containing both LA and ALA
Example:
Groundnut / Sesame / Rice bran / Cottonseed + Mustard/ Rapeseed
Groundnut /Sesame / Rice bran / Cottonseed + Canola
Groundnut / Sesame / Rice bran/ Cottonseed + Soyabean
Palmolein+ Soyabean
Safflower / Sunflower + Palm oil/ Palmolein + Mustard/ Rapeseed
92. Recommendations for visible fats cont..
(b) Oil containing high LA + oil containing moderate or low LA
Example:
Sunflower / Safflower + Palmolein / Palm oil / Olive oil
Safflower / Sunflower + Groundnut / Sesame / Rice bran /
cottonseed
93. Recommendations for visible fats cont..
2) Re Limit use of butter/ghee
3) Avoid use of PHVO as medium for cooking / frying
4) Replacements for PHVO
Frying : Use oils which have higher thermal stability
Ex:- palm, sesame, rice bran, cottonseed oil
(single / blends) ( home /commercial)
Food applications which require solid fats:
(Bakery food/ Indian sweets)
Use coconut oil/ palm oil / Palmolein