nutrition and human development chapters 4-7

What are lipids?

A diverse group of water-insoluble (hydrophobic) organic compounds including fats, oils, waxes, and steroids- composed primarily of carbon, hydrogen and oxygen

What’s the usefulness of fats?

1. Fuels stores- majority of energy stored as fat and the main form for excess food

2. Efficiency of fat stores-more effective way to store energy VS. glycogen; concentrated energy source

3. Organ protection- VITAL part of cell membranes

4. Transport fat/ raw materials

A) vitamin synthesis

B) hormone synthesis

Which type of foods are fats useful in?

1. Concentrated calories, especially for athletes

2. Fats soluble nutrients

3. Food appeal (crispy, tenderness, greasy, good texture and flavor)

4. Satiety

What are the three kinds of lipids?

1. Triglycerides

2. Phospholipids

3. Sterols

What is triglycerides?

Also known as fat- this kind of fat makes up 95% of the body’s fat

What are triglycerides made of?

Glycerol and three fatty acids

What do fatty acids differ in?

1. Length

2. Degrees of saturation

What’s a mufa?

Monounsaturated fats- One point of unsaturation (olive and avocado oil)

What’s a pufa?

Polyunsaturated fats- two points of unsaturation (sunflower and canola oil)

What’s the difference between saturated fats and unsaturated fats?

Saturated fats are mostly animal fats (butter and tropical fats) and unsaturated fats (mufa, pufa) are mostly plant fats

What are trans fats?

Makes cholesterol levels worse than saturated fats and causes the fat to clog arteries

What are phospholipids?

2 fatty acid chains and the third strand is a molecule with phosphorus which is hydrophilic attracted to H2O

What do phospholipids act as?

An emulsifiers which allow fats to blend with H2O for example, lecithin in egg yolks is a phospholipid and is an emulsifier (mayonnaise)

What are sterols?

Large molecules ex: cholesterol and plant sterols

What is the process of the LIPID transport?

Phospholipids, triglycerides and cholesterol is transported via lipoproteins which is a fat carrier made from lipids and proteins

What do lipoproteins carry?

• phospholipids

• triglycerides

• Cholesterol

• Proteins

What are the different lipoproteins?

1. LDL (low density lipoproteins)- larger, lighter, richer, more fat

2. HDL (high density lipoproteins)- smaller, denser, more protien

What are proteins made up of?

Amino acids

What are the two types of proteins?

1. Structural: tendons, ligaments, muscle tissue, scars, hair, nails, and the core of teeth

2. Working/ functional/ dynamic: antibodies, hormones, O2 carrier (hg= mercury), transport vehicles etc.

What are ploypeptides?

amino acids bound together by peptide bonds

What are the functions of protien?

1. Growth/ Maintenance/ Repair- growth spurts need dietary proteins

2. Enzymes- facilitate chemical reactions and breaking down food can only be done with enzymes

3. Hormones- protein component along with triglyceride/ sterols

4. Antibodies- giant protein muscles are active when antigen enters the body and it helps build immunity

5. Role in acid/base balance- (proteins have positive and negative charges) if not controlled it can go into acidosis/alkalosis

6. DNA- protien is present is EVERY CELL. The body has a memory of its own DNA (insulin is the same shape for everyone

What is denaturation?

a process where proteins or nucleic acids lose their native three-dimensional structure—and consequently their biological function—due to external stress such as heat, acids, or alkali

What are three factors that cause denaturation of protein?

1. Acid: HCL in stomach breaks into protein (electrical charge broken)

2. Heat: at 106 degrees fahrenheit and protein denatured

3. Enzymes: polypeptides broken down and amino acids broken down

What is protein synthesis?

The essential biological process where cells build proteins, which are necessary for structure, function, and the regulation of body issues

What happens when a cell needs to be replaced?

The mRNA leaves the nucleus with memory of DNA and then goes to the ribosome. After that, tRNA floats around in the cell and bring the correct amino acids to the mRNA and a chain is built

What is the stomachs job in protein digestion?

The acid and the enzymes break down the peptides

In protein digestion, what happens in the small intestine?

In the small intestinal wall, peptides are broken via enzymes until they become individual amino acids

What are the food sources for protien?

1 oz of meat= 7 grams of protein

1 slice of bread= 3 grams of protein

1 vegetable serving= 2 grams of protein

Why should we eat other proteins besides meat proteins?

Animal proteins have all essential amino acids and plants do not therefore we must eat a mixed diet so we get the full array of amino acids in an amino acid pool. If we only eat one type of food, we will be missing some

Why is it important to maintain protein in the body?

Gives nitrogen equilibrium in the body and adds nutrient balance especially for people using more nutrient than the body excretes for example pregnant women, teens, and body builders

What about people who are vegetarian, pescatarian, or vefan?

They have to be more aware because they can become deficient in vitamin B12, Fe, Zn

What are points of vitamins?

• indispensable to body fxs

• Needed in tiny amounts

• Essential

What are the 2 types of vitamins?

1. Fat soluble

2. Water soluble

What is a fat soluble vitamin?

• found in fats and oils

• Requires bile for absorption

• They travel on protein carriers

• Can reach toxic levels because they are stored in the liver and fatty tissue

• Deficiency in low fat diet/ fat malnutrition because have loss of fat (not absorbing)

What is a water soluble vitamin?

• freely travels in the bloodstream

• Absorbed directly into the bloodstream

• Most are not stored in the body instead the excess gets excreted in urine

• When you cook it can leech out in water

What does vitamin A contain?

3 active forms: retinol, retinal, retinoic acid

Precursor: beta-carotene

What are the roles in vitamin A?

1. Vision- plays role in light perception. In retina, there are cells with vitamin A

2. Gene expression- retinoic acid can deactivsaste or activate genes

3. Skin and body lining

What is the deficiency for vitamin A?

Night blindness (sure by eating liver)

Xeropthalmia- “dryness” cornea dries out blindness

*in the US its rare to have vitamin A deficiency

What is the toxicity for vitamin A?

Can come from supplements or fortified foods

• The upper limit is 3,000 micrograms

• Food sources don’t cause toxicity

* pregnant women who overuse supplements are at risk for fetal malfunctions

• smokers taking vitamin A will increase the risk of lung cancer

What are the sources for vitamin A?

Animal origin foods (other than liver, foods don’t cause toxicity)

What is beta-carotene?

Comes from the family of carotenoids which are colorful like Red, Yellow and orange pigmented foods

What happens when someone has excessive ingestion of beta-carotene?

Turn orange at lips and fingertips

What is the deficiency for beta-carotene?

Can develop macular degeneration

*The DRI for beta-carotene is 700 micrograms for women and 900 micrograms for men

What is vitamin D?

Also known as the “sunshine vitamin”

UV rays from the sun triggers synthesis of vitamin D

*darker skin doesn’t absorb sunlight as well

• melanin is responsible for pigmented skin

• Higher melanin=darker skin —> takes longer time for the suns rays to transform into vitamin D

What’s are the roles of vitamin D?

1. Regulates blood calcium and phosphorus levels

2. Hormone

*only vitamin with a duel role as a vitamin and a hormone (hormones travel and relay messages)

3. Cancer prevention- against colon, lung, and breast cancer

Which vitamins are good for bone health?

Vitamins A, K, D, and Calcium

When does vitamin D act as a hormone?

If calcium levels fall below physiological norms, vitamin D acts as a hormone and 1 out of the three things will occur:

1. Calls o whatever calcium in the GI tract to get it into the blood asap

2. Mobilizes calcium stores in the bone tissue to raise blood calcium levels

3. Goes to kidney and reabsorbs whatever is slated for excretion

What is the deficiency for vitamin D?

Only if you have fat malabsorption disorder or malnutrition

For kids it can cause rickets which are soft bones and treated with vitamin d containing foods and exposure to light

For adults it can causer osteomalacia which is the softening of bones includes pain and aching

What is the toxicity for vitamin D?

Thought to be most toxic of all vitamins likely from supplements but it can cause kidney problems if you take excessive supplements

What are the sources for vitamin d?

Sunlight exposure (wont cause toxicity)

Factors that effect sun exposure:

• skin color

• Where you live

• Sun screen

What are the recommendations for the vitamin D intake?

DRI: 19-50 years= 200 IU

51-70 years= 400 IU

70+ years = 600 IU

• as you age, your recommendation intake increases because of less sun exposure and less efficient at conversion

What are the compounds of vitamin E?

From the tocopherol family which includes - alpha, beta, gamma, delta

What are the compounds of vitamin E?

From the tocopherol family which includes - alpha, beta, gamma, delta

What is the deficiency for vitamin E?

The deficiency is rare because:

1. It’s widely available in foods

2. It’s stored in fatty tissues

• anyone with fat absorption disease is at risk for deficiency

• Premature babies are at risk because the mother transfers vitamin E in the 3rd trimester, so the baby may not recieve full transfer

What are the symptoms for deficiency for vitamin E?

• anemia- low vitamin e levels cause hemolytic anemia

• Neurological problems affecting nerves in feet and hands

What is the toxicity point for vitamin E?

Rare

• if on blood thinning meds, vitamin e can interact - has blood thinning effects