Vitamin A

 Vitamin A

Introduction

It is an essential human nutrient. It is a fat soluble vitamin

Vitamin A is a generic term for a large number of related compounds(2)

It can be divided into two categories

Ø  Retinoids: in foods of animal origin, the major form of vitamin A is an alcohol (retinol), or as an acid (retinoic acid),they are called performed vitamin A, but can also exist as an aldehyde (retinal).

Ø  Carotenoids : Precursors to the vitamin (a provitamin) are present in foods of plant origin( colored fruits and vegetables ), some of the members of the carotenoid family are beta-carotene, alpha-carotene, and beta- cryptoxanthin .

Among these, beta-carotene is most efficiently made into retinol . Alpha-carotene and beta- cryptoxanthin are also converted to vitamin A, but only half as efficiently as beta-carotene.

The discovery of vitamin A stemmed from research dating back to 1906 and it was the first lipo-soluble vitamin to be recognized by Moray 1922.

Sources

The richest food are (liver "beef, pork, chicken” , eggs , butter Milk and its products ).

carrots ,  Broccoli  , sweet potatoes , kale spinach .

Leafy vegetables , pumpkin , mango , apricots and papaya .

Fortified foods( low-fat , skim milk ,  margarine and most ready-to-eat and instant prepared cereals  )are often fortified with vitamin A because it is lost during processing ,  so  it is important to check the label on the package for the vitamin A content to obtain the RDA

2. Supplements:

The principal forms of preformed vitamin A (retinol ) are retinyl palmitate and retinyl acetate .

Beta carotene are common source of vitamin A in supplements.

Both may be combined in supplements

Equivalencies of retinoids and carotenoids (IU)

Vitamin A intake is often expressed in international units (IU) or as retinol equivalents (RE), with 1 micrograms retinol = 3.3 IU =6 micrograms beta carotene.

Recommended daily intake

Vitamin A US Dietary Reference Intake:

900 micrograms (3000 IU) for men

700 micrograms (2300 IU) for women.

Upper limit 3,000 micrograms (10,000 IU).

Role in the body :

Promoting vision (retinol – retinal )

Regulation of gene expression (retinoic acid )

Immunity (retinal and retinoic acid )

Supporting reproduction and growth(retinal)

Red blood cells production

Beta-carotene as antioxidant (4)

Disease Treatment

Vitamin A status

Vitamin A status depends on:

Adequacy of vitamin A stores , 90% of which are in the liver.

A person's protein status because retinol binding proteins serve as the vitamin's transport carriers inside the body .(4)

Nutrient interactions

Zinc

Zinc deficiency is thought to interfere with vitamin A metabolism in several ways affecting  vitamin A nutritional status in humans

Iron

Vitamin A deficiency may exacerbate iron deficiency anemia. (Moreover, studies in rats have shown that iron deficiency alters plasma and liver levels of vitamin A)

Deficiency
 Children who are considered to be at increased risk for subclinical vitamin A deficiency include:

Preschool age children.

Children living at or below the poverty level.

Children with inadequate health care or immunizations.

Children living in areas with known nutritional deficiencies.

Children with diseases of the pancreas, liver, or intestines, or with inadequate fat digestion or absorption.

Manifestations of hypovitaminosis

Night blindness, corneal drying (xerosis), triangular gray spots on eye (Bitot's spots), corneal degeneration and blindness (xerophthalmia) , impaired immunity (Vitamin A deficiency can be considered a nutritionally acquired immunodeficiency disease) , hypokeratosis (white lumps at hair follicles), softening of the cornea (keratomalacia).

Children who are only mildly deficient in vitamin A have    a higher incidence of respiratory disease and diarrhea as well as a higher rate of mortality from infectious  diseases

Vitamin A deficiency in the opt :

22% of children were found to have low vitamin -A plasma levels (<200 μg/L) , Furthermore, more than half of the children participating in the study (53.9%) had levels of vitamin A in the range of 200-299 μg/L , meaning that 75.9% of children had vitamin A levels below 300 μg/L.

The results showed a significant difference between the prevalence of vitamin A deficiency in the West Bank (18.9 per cent) compared to the Gaza Strip (26.5 per cent), but no difference with respect to gender, age groups or refugee status.

Overdose and toxicity
( Hypervitaminosis )

As vitamin A is fat-soluble, disposing of any excesses leads to toxicity.

Children are more vulnerable to toxicity because they need less and are more sensitive to overdoses

vitamin A toxicity occurs when all binding proteins are swamped and free vitamin A damages the cells .

Acute toxicity generally occurs at doses of 25,000 IU/kg.This can lead to nausea, jaundice, irritability, anorexia vomiting, blurry vision, headaches, muscle and abdominal pain and weakness, drowsiness and altered mental status.

Chronic toxicity occurring at 4,000 IU/kg daily for 6-15 months.In chronic cases, hair loss, drying of the mucous membranes, fever, insomnia, fatigue, weight loss, bone fractures, anaemia, and diarrhoea (5)

Overdose and toxicity
( Hypervitaminosis )

Liver toxicities can occur at levels as low as 15,000 IU per day to 1.4 million IU per day, with an average daily toxic dose of 120,000 IU per day.

In people with renal failure 4000 IU can cause substantial damage.

Beta carotene from food is likely to cause this toxicity as it is not converted efficiently enough in the body to vitamin A , it is stored in the fat just under the skin and turn skin yellow . In contrast from supplement is harmful.

Excessive vitamin A over years weakens the bone and contribute to osteoporosis

Birth defects and Safety in pregnancy

Excessive vitamin A  has a teratogenic risk (10000 IU before 7th week of pregnancy).

Some current issues and controversies about vitamin A

Since 1987, WHO has advocated the routine administration of vitamin A with polio, multi-antigen and measles vaccine in countries where vitamin A deficiency is a problem, also supplementation to  postpartum mothers can improve the vitamin A content of their breast milk.(6)

Vitamin A, beta carotene, and cancer

Dietary intake studies suggest an association between diets rich in beta-carotene and vitamin A and a lower risk of many types of cancer

Fontham ETH. Protective dietary factors and lung cancer. Int J Epidemiol 1990;19:S32-S42. [PubMed abstract]

Vitamin A and osteoporosis limited experience data

Results of some studies indicate that long term intake of performed vitamin A of 1500 mcg /day ( not beta carotenes) increases risk of osteoporotic fracture by affecting mineral bone density .

Recommendation to obtain adequate vitamin A :

Vitamin A can be lost from foods during preparation, drying , or storage. To prevent loss of vitamin A:

Use raw fruits and vegetables whenever possible.

Keep vegetables (except sweet potatoes) and fruits covered and refrigerated during storage.

Steam vegetables and braise, broil meats instead of frying. Some of the vitamin A is lost in the fat during frying.

Food labeling to obtain RDA and avoid overdose .

Fortified foods and supplementations

Extra vitamin A to prevent deficiency

World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) recommend vitamin A administration for all children diagnosed with measles,” Measles may increase the body's utilization of vitamin A, possibly because of the rapid destruction of epithelial surfaces”,  in communities where vitamin A deficiency is a serious problem and where death from measles is greater than 1%.

Fat malabsorption can result in diarrhea and prevent normal absorption of vitamin A ( Celiac disease, Crohn's disease, and Pancreatic disorders)

Vegetarians: should choose dark green leafy vegetables and orange and yellow fruits to consume recommended amounts of vitamin A

 Give supplements to postpartum women and promoting breastfeeding is the best way to protect babies from VAD.

For deficient children: periodic supply of high-dose vitamin A is indicated .

Vitamin A supplementation reduces severe morbidity and mortality from infectious diseases among children .

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Cystic Fibrosis Nutrition

Cystic Fibrosis - Nutrition

 Cystic Fibrosis

n  Cystic Fibrosis (CF) is an incurable disorder that is inherited autosomal recessively.

n  It mainly affects the respiratory system and the digestive system.

n  The body secretes an abnormally thick mucus causing an obstruction in the lungs and the pancreas.

n  Cystic Fibrosis - continued

n  The abnormal mucus secretion in the lungs leads to breathing problems and repeated respiratory infections, such as pneumonia and bronchitis.

n  In the pancreas, the mucus interferes with digestive enzymes and its ability to secrete the hormone insulin (needed to break down sugar), making it difficult to effectively digest food and absorb the nutrients.

n  Understanding CF

n  Epidemiology

n  Affects 1 in every 3000 Caucasian babies born

n  30,000 people in the US (70,000 worldwide)

n  In Gaza Strip there are 48 cases diagnosed with

   CF.

n  In Jordan CF affects about 1 per 2560 newborn,

    while in Egypt it affects 1 per 4000 newborn.

n  30% of patients are adults

n  Cause of CF

n  CF is caused by a defect in the gene CFTR (Cystic Fibrosis Transmembrane Conductance), a protein found in cells that line the lungs, digestive tract, sweat glands, and the genitourinary system.

n  It controls the flow of chloride ions in and out of these cells.

n  In a healthy person, CFTR forms a channel in the plasma membrane allowing chloride ions to enter and leave the cells. In a person with CF, the CFTR prevents chloride from entering or leaving the cells, resulting in the thick mucus that causes the obstruction.

n      

n  Symptoms of Cystic Fibrosis

n  Can very from person to person

n  They can become apparent shortly after birth or can go undetected for months or years.

n  The most common symptom is intestinal blockage in newborns (meconium ileus).

n  Others symptoms can include bulky or greasy stool, poor weight gain or abnormal weight loss.

n  Shortness of breath, wheezing, persistent cough producing a thick mucus

n  Frequent respiratory infections, such as Pseudomonas aeruginosa or abnormally salty sweat and dehydration. 

n  Symptoms of Cystic Fibrosis

  

n  Diagnosing CF

n  Symptoms suggestive of CF are exhibited by the patient.

n  A sweat chloride test also known as Sweat Test

n  Measures the amount of salt in the sweat

¨  Positive test - >60 mEq/L

¨  Negative - <40 mEq/L

        

n  Diagnosing CF - continued

n  There are various other tests used to diagnose Cystic Fibrosis such as:

          1.  DNA testing

          2.  Fecal fat Test

          3.  Upper GI and small bowel series

          4.  Measurement of pancreatic function

n  CF gene mutation is useful for diagnosing CF as well as determining CF carriers

n  Pulmonary function tests (PFTs) are breathing tests that help measure lung reserve and degree of airflow obstruction

n  Complications

n  Pancreatic Insufficiency

n  Pulmonary Manifestations

n  Growth Complications

n  Insulin Dependent diabetes

n  Distal Intestinal Obstruction Syndrome and Constipation

n  Bone disease

n  Managing CF

n  Tobramycin for lung infections caused by bacteria.

n  Decongestants, bronchodilators (drugs that open airways congested with mucus) and anti-inflammatory drugs.

n  Nutritional therapy (high-protein, high-calorie diet with vitamin supplements)

n  Pancreatic enzymes to aid in digestion

n  Managing CF - continued

n  Chest physical therapy or postural drainage (chest or back clapping) helps to loosen and drain the mucus from the lungs.

n  Newer treatments include inhalation of a spray containing normal copies of the CF gene, which will deliver the correct copy of the CF gene into the lungs.

n  Also, protein repair therapy aims at repairing the defective CFTR protein.

n  Factors associated with poor nutrition

n  Increased stool losses of nutrients.

n  Anorexia and poor dietary intake.

   

n  Increased energy demands of the disease.

n  Abnormal adaptive response to malnutrition

n  Cystic Fibrosis - Nutrition

n  The energy needs of patients with CF have been stated as 120-150% of those required by healthy individuals of the same age, sex and size.

n  This reflects an increase in the basal metabolic rate (BMR) as a result of increase in the work of breathing. Infection and inflammation also increase the energy Demands

n  Fewer of the energy-producing nutrients are

    properly digested and absorbed into the

    body, even when treatment is optimal.

.

n  Increasing Energy Requirements

n  3 meals and 3 snacks

n  Supplemental milkshakes

n  Foods to add calories

¨  Whole milk, cheese, butter, margarine, oil

¨  Peanut butter spread

¨  Ice cream or whole milk yogurt

¨  Salad dressing and mayo

¨  Cream or half and half

¨  Cream cheese

¨  Sour cream

¨  Powdered milk

¨  At least one portion of starchy food should be offered with every meal (potatoes, bread, cereals, rice, biscuits and pasta)

n  Protein Requirements

n  Protein is necessary for growth and

    maintenance of body tissues, and proper

    functioning of the immune system.

    1.5-2 times the DRI for age

n  Most people with CF have higher-than-usual

    protein requirements.

n  Reference nutrient intake for protein:

n  Protein 0-3 month 4-6 month 10-12 month

n  (g/day)    12.5          12.7             14.9

n  Protein Requirements

n  Most high-protein foods are of animal

    origin, including milk and milk products,

    meats, poultry, fish, and eggs.

n   Legumes, such as peas, beans, and

     lentils, are also good sources of protein,

     especially when eaten with cereals.

n  High-protein, high-calorie
foods

n   Whole-milk products, such as yogurt,

     cheese, custard, and pudding.

n   Beverages made with whole milk or

     undiluted evaporated milk, such as

     milkshakes.

n   Nuts, nut butters (especially peanut)

     and halawa.

n   Meat, fish, poultry, or eggs prepared

     with added fat.

n  Fat Requirements

n  35-40% of calories

n  Fat provides more than twice as many

   calories as protein or carbohydrate.

n  Conversion of fat to energy requires

    less oxygen than conversion of protein

    or carbohydrate to energy, putting less

    of a burden on the respiratory system.

n  Fat Requirements

n   Fats are essential for the body to

     properly absorb vitamins A, D, E, and K.

n   Adequate dietary fat is required for

     provision of essential fatty acids.

n   Generally, individuals with CF have a

     low blood cholesterol level and

     therefore do not have to restrict the

     intake of saturated fat and cholesterol.

n  Vitamins Intake

n  Fat soluble vitamin deficiencies common

n  The daily requirement of fat-soluble vitamins

    in CF is about twice the normal recommended

    values for age

n  Monitor overdosing

¨  Patient instruction

¨  Yearly monitoring of serum levels

n  People with CF need about 50-200 mg of

    vitamin E daily.

n   Vitamins are absorbed most effectively when

    taken with fat-containing meals and PRT.

n  Salt Intake

n  People with CF lose more salt (sodium

   chloride) in their sweat than other individuals.

   Their need for additional salt is usually met

   simply by increasing intake of normal foods in

   order to meet caloric requirements.

n  Na requirements increased

¨  Monitor in hot weather, fever, physical exertion

¨  Sports drinks with electrolytes

n  Dairy Products

n   Cystic fibrosis patients tend to have less

     bone density. so

n   Drink at least 3cups of milk daily.

n   Take enough vitamin D and K.

n   Ensure adequate sun exposure.

n   Exercise daily to maintain bone mass

n   and help to clear the chest.

n  NSP (Fiber)

n  Children with CF should be encouraged

    to eat some foods which are rich in

    fiber to help maintain normal bowel

    function and prevent constipation.

   However, too much fiber is very filling

   and may reduce your child’s intake of

   high energy foods.

n  These foods also contain ‘photochemical’ which may help the body to fight infection

n  Water

n  Patients with CF should consume plenty

    of water.

n  Proper hydration helps to decrease the

n  viscosity of sputum.

n  Avoid caffeine

n  Encourage your child to drink 6 – 8 cups of fluid daily.

n  fruit and vegetables?

n  These foods are not high in calories, but they are valuable source fiber ,vitamins and some minerals

n  Encourage 3-5 portions daily

n  Stir frying vegetables will increase their calorie value.

n  Adding a knob of butter to vegetables increases the calories.

n  Modifying intake of regular foods

n  If caloric and nutrient requirements are

    to be increased, modify intake by

    following these four steps:

n  Increase portion sizes.

n   Add snacks and “mini-meals”.

n  Emphasize high-protein, high-calorie foods.

n  Add extra healthy fats- Fry foods.

n  Pancreatic Replacement
Therapy (PRT)

n  85-90% pancreatic insufficiency

n  (pancreatic insufficiency )very little or no pancreatic enzymes

n  enzyme requirements will differ

n  The dose of (PRT) is 1-2 capsules/kg of the average weight of the child (and not per the current weight), PLUS 20% of this dose to cover the increased basal metabolic rate.

n  Pancreatic Replacement
Therapy (PRT)

n  Then adjust the dose according to weight gain and stool character, as proper dose (PRT) promote weight gain, and prevent or minimize steatorrhoea

n  pancreatic enzymes may be inactivated by elevated gastric and duodenal acidity.

n  The use of H2 receptor antagonists or perhaps PPI should then be considered

n  Enzyme Dosing

n  Creon (microsphere)

¨  Creon 5 = 5000 units lipase/capsule

¨  Creon 10 = 10,000 units lipase/capsule

¨  Creon 20 = 20,000 units lipase/capsule

n  Pancrease MT

¨  4, 10, 16 and 20 (number x 1000 = units lipase/capsule)

n  Ultrase

¨  4500 units/capsule

n  Ultrase MT

¨  12, 18 and 20 (number x 1000 = units lipase/capsule)

n  How should pancreatic
enzymes be taken?

n   Do not mix the enzymes with hot food.

n   Do not allow your child to chew the granules.

n   Distribute the required dose of Creon over 3 main meals and 2-3 snacks.

n   Do not try to dissolve enzymes in water

     or milk as they will never dissolve.

n   Fatty meals will need more enzymes, than low fat      meals.

n  How should pancreatic
enzymes be taken?

n  give enzymes at the beginning and part through a meal

n  For older children who cannot swallow the capsule, open the capsules and mix the microtablets with a small amount of food.

n  Treatment of CF is not curative and must be continued throughout life.

n  Foods that do not require
PRT

n   Fruits (except avocado)

n   Vegetables, (except potatoes & beans)

n   Honey, jam, sugar

n   Jelly, candy

n   Soft drinks, tea and coffee.

n  How will I know if the amount of enzyme is correct?

n  There are several signs which may mean that the     dose of enzymes is incorrect:

n  Pale, floaty stools which are difficult to flush away.

n   Increased stool frequency.

n   Abdominal pain, bloating, flatulence or wind.

n   Poor weight gain.

n  Summary

n  Cystic Fibrosis is an autosomal disorder that affects the lungs and the pancreas

n  It is caused by a defect in the CFTR protein, resulting in obstruction due to excess mucus

n  Patient treated with Motrin for fever and Tobramycin for Pseudomonas aeruginosa infection

n  Receiving Pulmozyme inhalation therapy and Creon for CF

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