Micronutrient Deficiencies: Iodine, Iron, Vitamin A & Folate
Micronutrient Deficiencies
Iodine Deficiency
Iodine is an essential trace element.
Requirements:
- 110-130 μg for infants up to 12 months
- 90 μg for children up to 8 years
- 130 μg for children up to 13 years
- 150 μg for adults
- 220 μg for pregnant women
- 290 μg for lactating mothers
Main Role:
Constituent of thyroid hormones thyroxine (T4) and triiodothyronine (T3).
The thyroid gland needs no more than 70 μg/day to synthesize the requisite daily amounts of T4 and T3.
Sources:
- Seafood (fish, kelp, shellfish)
- Dairy products (milk, cheese, eggs)
- Plants grown on iodine-rich soil
- Iodized salt (fortified with iodine)
Iodine Deficiency:
Leading cause of preventable intellectual disability.
Hypothyroidism:
- Extreme fatigue
- Goiter
- Mental slowing
- Depression
- Weight gain
- Low basal body temperatures
The addition of iodine to table salt has largely eliminated this problem in wealthier nations.
Other Possible Health Effects:
- Breast Cancer: The breast concentrates iodine into breast milk. Low iodine levels may lead to hyperplasia, sometimes manifesting as fibrocystic breast disease.
- Stomach Cancer: Some research has found a correlation between iodine deficiency, iodine-deficient goiter, and gastric cancer. A decrease in stomach cancer mortality has been reported after implementing iodine prophylaxis.
- Autism: Research suggests that mothers with low iodine levels are more likely to have an autistic child.
World Distribution:
2 billion people worldwide, particularly in the Western Pacific, South-East Asia, and Africa.
Prophylaxis:
Iodized salt
Iron Deficiency
- One of the most common nutritional deficiencies.
- Roles: Carries oxygen, transports electrons, and is integral to enzyme reactions.
- Sources: Red meat, poultry, lentils, beans, leafy vegetables, pistachios, tofu, etc.
- Deficiency: Anemia
- Risk Groups: Children and pre-menopausal women
- Causes: Chronic bleeding, inadequate intake, substances interfering with iron absorption, malabsorption syndromes, etc.
- Symptoms: Pallor, fatigue, headache, dizziness, weakness, brittle spoon-shaped nails, Plummer-Vinson syndrome, etc.
- Treatment: Treat the cause and use iron supplements if necessary.
Vitamin A Deficiency
A group of nutritional organic compounds including retinol, retinal, retinoic acid, and several provitamin A carotenoids (beta-carotene is the most important).
Functions:
- Growth and development
- Maintenance of the immune system
- Good vision
Sources:
Carrots, liver, broccoli, spinach, eggs, etc.
Causes:
- Primary: Diets low in animal sources of pre-formed vitamin A
- Secondary: Chronic malabsorption of lipids, impaired bile production and release, chronic exposure to oxidants (e.g., cigarette smoke), and chronic alcoholism
Signs and Symptoms:
- Night blindness: One of the first signs of deficiency
- Xerophthalmia (dryness of the conjunctiva) and complete blindness (Vitamin A plays a role in phototransduction)
- Decreased immunity and ability to fight infections (e.g., higher measles fatality rates in countries with low immunization rates)
- Enamel hypoplasia
Adequate vitamin A intake during pregnancy and breastfeeding is crucial for fetal development and breast milk. Deficiencies cannot be fully compensated by postnatal supplementation.
Treatment:
Oral and injectable forms of vitamin A, generally as vitamin A palmitate.
Folate Deficiency
Functions:
Synthesizes DNA, repairs DNA, methylates DNA, and acts as a cofactor in biological reactions involving folate. It is crucial for rapid cell division and growth (e.g., infancy and pregnancy).
Sources:
Leafy vegetables, egg yolks, legumes, sunflower seeds, etc.
Deficiency:
Glossitis, diarrhea, depression, confusion, megaloblastic anemia, and fetal neural tube defects and brain defects (during pregnancy).
Note: Alcohol consumption accelerates folate deficiency.
Causes:
- Increased need for folate
- Inadequate intake
- Increased excretion
- Medications
Symptoms:
- Loss of appetite and weight loss
- Weakness
- Sore tongue
- Headaches
- Heart palpitations
- Irritability
- Behavioral disorders
- Depression
- Premature and low birth weight infants
Treatment:
Folic acid supplementation