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تحميل الدليل التدريبي

أسئلة شائعة


Food hazard:

Favism: [Ital. favismo, from fava, bean]

Favism: Hemolytic anemia resulting from eating fava beans; victims have an inherited blood abnormality and enzyme deficiency.

An acute condition suffered after ingestion of certain species of beans, e.g., Vicia faba, or inhalation of the pollen of its flower; characterized by fever, headache, abdominal pain, severe anemia, and coma.


It occurs in some people with genetic erythrocytic deficiency of glucose 6-phosphate dehydrogenase in the red blood cells. which are then vulnerable to the toxins, vicine and convicine, in the beans.


The condition affects some 100 million people world-wide, and is commonest in people of Mediterranean and Middle-East regions.



Milk intolerance:

What is lactose intolerance?

Lactose intolerance is the inability or insufficient ability to digest lactose, (a sugar found in milk and milk products).

Lactose intolerance is caused by a deficiency of the enzyme lactase, which is produced by the cells lining the small intestine.

Lactase breaks down lactose into two simpler forms of sugar called glucose and galactose, which are then absorbed into the bloodstream.

Not all people with lactase deficiency have digestive symptoms. Most people with lactose intolerance can tolerate some amount of lactose in their diet.

People sometimes confuse lactose intolerance with cow milk allergy. Milk allergy is a reaction by the body’s immune system to one or more milk proteins and can be life threatening when just a small amount of milk or milk product is consumed.

Milk allergy most commonly appears in the first year of life, while lactose intolerance occurs more often in adulthood.

What causes lactose intolerance?

The cause of lactose intolerance is best explained by describing how a person develops lactase deficiency.

Primary lactase deficiency develops over time and begins after about age 2 when the body begins to produce less lactase. Most children who have lactase deficiency do not experience symptoms of lactose intolerance until late adolescence or adulthood.

Researchers have identified a possible genetic link to lactase deficiency:

Primary: Some people inherit a gene from their parents that makes it likely they will develop primary lactase deficiency.

Secondary: lactase deficiency results from injury to the small intestine that occurs with severe diarrheal illness, celiac disease, Crohn’s disease, or chemotherapy. This type of lactase deficiency can occur at any age but is more common in infancy.

What are the symptoms of lactose intolerance?

People with lactose intolerance may feel uncomfortable 30 minutes to 2 hours after consuming milk and milk products. Symptoms range from mild to severe, based on: the amount of lactose consumed and the amount a person can tolerate.

Common symptoms include

·                     abdominal pain

·                     abdominal bloating

·                     gas

·                     diarrhea

·                     nausea

How is lactose intolerance diagnosed?

Lactose intolerance can be hard to diagnose based on symptoms alone. People may think they suffer from lactose intolerance because they have digestive symptoms; however, other conditions such as irritable bowel syndrome can cause similar symptoms.

# After taking a medical history and performing a physical examination, the doctor may first recommend eliminating all milk and milk products from the person’s diet for a short time to see if the symptoms resolve.

#Two tests are commonly used to measure the digestion of lactose.

1- Hydrogen Breath Test. The person drinks a lactose-loaded beverage and then the breath is analyzed at regular intervals to measure the amount of hydrogen. Normally, very little hydrogen is detectable in the breath, but undigested lactose produces high levels of hydrogen. Smoking and some foods and medications may affect the accuracy of the results. People should check with their doctor about foods and medications that may interfere with test results.

2- Stool Acidity Test. The stool acidity test is used for infants and young children to measure the amount of acid in the stool. Undigested lactose creates lactic acid and other fatty acids that can be detected in a stool sample. Glucose may also be present in the stool as a result of undigested lactose.

How is lactose intolerance managed?

Gradually introducing small amounts of milk or milk products may help some people adapt to them with fewer symptoms. Often, people can better tolerate milk or milk products by taking them with meals.

The amount of change needed in the diet depends on how much lactose a person can consume without symptoms. For example, one person may have severe symptoms after drinking a small glass of milk, while another can drink a large glass without symptoms. Others can easily consume yogurt and hard cheeses such as cheddar and Swiss but not milk or other milk products.

The Dietary Guidelines for Americans 2005 recommend that people with lactose intolerance choose milk products with lower levels of lactose than regular milk, such as yogurt and hard cheese.

Lactose-free and lactose-reduced milk and milk products, available at most supermarkets, are identical to regular milk except that the lactase enzyme has been added.

Lactose-free milk may have a slightly sweeter taste than regular milk. Soy milk and other products may be recommended by a health professional.

People who still experience symptoms after dietary changes can take over-the-counter lactase enzyme drops or tablets. Taking the tablets or a few drops of the liquid enzyme when consuming milk or milk products may make these foods more tolerable for people with lactose intolerance.

Lactose Intolerance and Calcium Intake

Milk and milk products are a major source of calcium and other nutrients. Calcium is essential for the growth and repair of bones at all ages. A shortage of calcium intake in children and adults may lead to fragile bones that can easily fracture later in life, a condition called osteoporosis.

Women who are pregnant or breastfeeding need between 1,000 and 1,300 mg of calcium daily.

Getting enough calcium is important for people with lactose intolerance when the intake of milk and milk products is limited. Many foods can provide calcium and other nutrients the body needs. Non-milk products that are high in calcium include fish with soft bones such as salmon and sardines and dark green vegetables such as spinach.

Calcium is absorbed and used in the body only when enough vitamin D is present. Some people with lactose intolerance may not be getting enough vitamin D. Vitamin D comes from food sources such as eggs, liver, and vitamin D-fortified milk and yogurt.

Regular exposure to sunlight also helps the body naturally absorb vitamin D.

What other products contain lactose?

Milk and milk products are often added to processed foods—foods that have been altered to prolong their shelf life. People with lactose intolerance should be aware of the many food products that may contain even small amounts of lactose, such as

·                     bread and other baked goods

·                     waffles, pancakes, biscuits, cookies, and mixes to make them

·                     processed breakfast foods such as doughnuts, frozen waffles and pancakes, toaster pastries, and sweet rolls

·                     processed breakfast cereals

·                     instant potatoes, soups, and breakfast drinks

·                     potato chips, corn chips, and other processed snacks

·                     processed meats, such as bacon, sausage, hot dogs, and lunch meats

·                     margarine

·                     salad dressings

·                     liquid and powdered milk-based meal replacements

·                     protein powders and bars

·                     candies

·                     non-dairy liquid and powdered coffee creamers

·                     non-dairy whipped toppings

Checking the ingredients on food labels is helpful in finding possible sources of lactose in food products. If any of the following words are listed on a food label, the product contains lactose:

·                     milk

·                     lactose

·                     whey

·                     curds

·                     milk by-products

·                     dry milk solids

·                     non-fat dry milk powder

Lactose is also used in some prescription medicines, including birth control pills, and over-the-counter medicines like products to treat stomach acid and gas. These medicines most often cause symptoms in people with severe lactose intolerance

Vitamin poisoning:

hypervitaminosis or vitamin overdose refers to a condition of high storage levels of vitamins, which can lead to toxic symptoms. The medical names of the different conditions are derived from the vitamin involved: an excess of vitamin A, for example, is called hypervitaminosis A.

With few exceptions, like some vitamins from B complex, hypervitaminosis usually occurs more with fat-soluble vitamins, which are stored in the liver and fatty tissues of the body. Because of this, these vitamins build up and remain for a longer time in the body than water soluble vitamins.

High dosage vitamin A; high dosage, slow release vitamin B3; and very high dosage vitamin B6 alone (i.e. without vitamin B complex) are sometimes associated with vitamin side effects.

Vitamin C has a brief, pronounced laxative effect when taken in large amounts, typically in the range of 5-20 grams per day in divided doses for a person in normal "good health," although seriously ill people,  may take 100-200 grams without inducing vitamin poisoning.

High doses of mineral supplements can also lead to side effects and toxicity. Mineral-supplement poisoning does occur occasionally due to excessive and unusual intake of iron-containing supplements, including some multivitamins, but is not common.

1- Hypervitaminosis A

Hypervitaminosis A refers to the effects of excessive vitamin A (specifically retinoid) intake.

Effects include:

·                     birth defects

·                     liver problems

·                     reduced bone mineral density that may result in osteoporosis

·                     coarse bone growths

·                     skin discoloration

·                     hair loss

·                     excessive skin dryness/peeling (desquamation)


Signs of acute toxicity include nausea and vomiting, headache, dizziness, blurred vision, and loss of muscular coordination.Pathophysiology

Hypervitaminosis A occurs when the maximum limit for liver stores of retinoids is exceeded. The excess vitamin A enters the circulation causing systemic toxicity.

Betacarotene, a precursor of vitamin A, is selectively converted into retinoids, so it does not cause toxicity.

Most multivitamins contain vitamin A doses below 10,000 IU, therefore multi-vitamins are unlikely to cause vitamin A toxicity when taken at their recommended dosage.

Recommended supplement limits

These levels for preformed vitamin A in micrograms (µg) and International Units (IU) are:

·                     0-3 years: 600 µg or 2000 IU

·                     4-8 years: 900 µg or 3000 IU

·                     9-13 years: 1700 µg or 5665 IU

·                     14-18 years: 2800 µg or 9335 IU

·                     19+ years: 3000 µg or 10,000 IU

2- Hypervitaminosis D is a state of vitamin D toxicity.

The recommended daily allowance is 400 IU per day. Overdose has been observed at 1925 µg/d (77,000 IU per day).

Acute overdose requires between 15,000 µg/d (600,000 IU per day) and 42,000 µg/d (1,680,000 IU per day) over a period of several days to months, with a safe intake level being 250 µg/d (10,000 IU per day).

Foods contain low levels, and have not been known to cause overdose. Overdose has occurred due to industrial accidents, for example when incorrectly formulated pills were sold or missing industrial concentrate cans misused as cans of milk.

Symptoms and presentation

Symptoms of vitamin D poisoning include:

·                     Dehydration

·                     Vomiting

·                     Decreased appetite (anorexia)

·                     Irritability

·                     Constipation

·                     Fatigue

An excess of vitamin D causes abnormally high blood concentrations of calcium (hypercalcemia), which can cause overcalcification of the bones, soft tissues, heart and kidneys. It can also damage the kidney and produce kidney stones. In addition, hypertension can result.

Ongoing research indicates antagonism with oil soluble menatetrenone, MK-4, an internally transported natural form of vitamin K2, which is associated with bone formation and calcium retention in the bones.

Note: Hypervitaminosis D symptoms appear several months after excessive doses of vitamin D are administered.

3- Hypervitaminosis E

Hypervitaminosis E is a state of Vitamin E toxicity. Because vitamin E can act as an anticoagulant and may increase the risk of bleeding problems, many agencies have set an upper tolerable intake level (UL) for vitamin E at 1,000 mg (1,500 IU) per day.

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