Nutrition Module #4: Nutritional Anemias Flashcards
Who are the 11 populations at risk for folate deficiency?
- Adolescents: poor intake
- Elderly: poor intake, malabsorption, medications that may interfere with metabolism (barbiturates)
- Alcoholics: poor intake, alcohol interfering with metabolism
- Premature babies: increased needs
- Pregnant women: increased needs
- Malabsorption diseases: celiac’s disease, HIV, Crohn’s
- Low-income: limited access to fresh veggies
- Psoriases (and other skin diseases) patients: increase loss of folate
- Women who take oral contraceptives: increase loss of folate
- Kids during rapid growth: increased folate requirements
- Patients with hemoglobinopathies: increased erythropoiesis
Are there any specific symptoms for folate and B12 deficiencies?
NOPE
What are the 9 non-specific symptoms of folate deficiency?
- Loss of appetite
- Irritability*
- Hostility
- Diarrhea*
- Paranoia
- Forgetfulness
- Depression*
- Macrocytic anemia*
- Increased homocysteine blood concentration
What is the risk of folate deficiency on a fetus?
Neural tube defects
What is the risk of folate deficiency in adults?
Cancer and CVD
What are the different forms of folate?
They have 3-8 glutamate residues
Which form of folate can cross cell membranes?
Monoglutamate folate
What do polyglutamate folate serve as? Which kind?
Coenzyme that accept or donate 1 C units in :
- DNA synthesis
- Catabolism or interconversion of Met, His, Ser, and Gly
- Choline synthesis and degradation
Fully reduced tetrahydrofolate
How do we regenerate methionine from homocysteine? Why is this needed?
We need folate and B12
Methionine donates a methyl group forming homocysteine
What 3 nutrients are needed for normal neural tube closure?
- Folate
- B6
- B12
Which have a higher bioavailability of folate: vegetables or supplements?
Supplements
Where is folate found in the body? 2 places.
- Blood bound to albumin (monoglutamates)
2. Liver
What are the 2 lab tests to detect folate deficiency? What is each a measure of?
- Serum folate: recent folate intake
2. RBC folate: liver folate levels (past intakes)
What is megaloblastic anemia caused by? Symptoms?
Cause: folate and B12 deficiency
Symptoms: macrocytic anemia, segmented neutrophils, absence of platelets, megaloblasts (large nucleated RBCs), diarrhea, malabsorption of nutrients
What are the 5 stages of folate deficiency?
- Serum folate decreases
- RBC folate and liver folate decrease
- Hypersegmented neutrophils appear
- Mean corpuscular volume increases
- Serum hemoglobin decreases
What can increase serum folate other than increase intake?
B12 deficiency
What can decrease serum folate other than poor intake?
- Smoking
- Estrogen
- Contraceptives
What can increase RBC folate other than increase intake?
- Reticulocytosis
2. Fe deficiency
What can decrease RBC folate other than decrease intake?
B12 deficiency
How to distinguish between folate and B12 deficiencies? 1 test
Serum (more sensitive) or urine methylmalonyl-CoA: if elevated, B12 deficiency because needed to convert it to succinyl CoA
What are 6 good food sources of folate?
- Fresh dark leafy veggies
- Legumes
- Cereal
- Citrus fruits
- Organ meats
- Yeast
What can decrease the folate content of vegetables?
Boiling them
What is the normal folate daily requirement?
2-3 servings of folate-rich foods
How much folate supplement should be given when necessary?
200-400 microg
What are the 4 populations at risk of B12 deficiency?
- Elderly: low intake, poor absorption
- Vegans: low intake
- Hyperthyroidism
- Fish tapeworm or bacteria in ileum
What are the 2 clinical symptoms of B12 deficiency?
- Indigestion
2. Diarrhea*
What are the 4 psychiatric symptoms of B12 deficiency?
- Depression*
- Irritability*
- Confusion
- Dementia
What are the 2 symptoms of B12 deficiency seen in the elderly?
- Enlarged spleen/liver
2. Congestive heart failure
What are the 6 peripheral neuropathies seen with B12 deficiency? What are these due to? Are these reversible?
- Bilateral vision loss
- Loss of coordination
- Loss of postural sense
- Loss of vibration sense in feet
- Symmetric abnormal sensations in feet/hands
- Reduced sensations of pain, temperature, and touching
Due to inadequate myelin synthesis
Reversible if treated quickly
What do B12 and folate symptoms have in common?
Anemia with hypersegmented neutrophils and some psych/clinical symptoms
Describe the 3 steps of B12 absorption.
- Stomach: gastric acid, peptin, and intrinsic factor 1 release B12 from proteins
- Duodenum: same and B12 forms a dimer with IF-1
- Ileum: B12-IF-1 binds to receptors which requires Ca2+/Mg2+ and a pH
What can inhibit the dimerization of B12 and IF-1 in the duodenum?
Too much acid
What molecules transport B12 in the blood?
Transcobalamins (TC-II)
Where is B12 stored?
Liver
How much B12 is stored in the liver?
1-10 mg
How long do B12 stores last?
- 3-6 months after cessation of absorption
- 20-30 years after cessation of intake
Why is B12 so well preserved in the body?
Because you can only lose it in bile which is reabsorbed
What are the 3 lab tests to detect B12 deficiency? What is each a measure of?
- Serum B12
- Methylmalonic CoA (serum or urine)
- Schilling test: determines whether malabsorption is the cause by measuring radioactive B12 in the urine when provided with and without IF-1
What can serum B12 be decreased by other than deficiency?
- Fe deficiency
- Folate deficiency
- Pregnancy
- Multiple myeloma
How do B12 stores change with age?
They increase
What are 2 food sources of B12? What do they have in common?
- Animal foods
- Yeast
Both provide B12 from microbial origins
Does food processing/cooking have an effect on B12 content?
NOPE
What is the treatment for B12 malabsorption?
Injections of cyanocobalamin or high-dose B12 supplement (IF-1 is too expensive)
What does a decrease in the mean corpuscular volume suggest?
Iron deficiency
What is the diagnosis if serum hemoglobin and RBC are low but mean corpuscular volume is normal?
Normocytic anemia
When should women start taking a folate supplement?
When they are trying to conceive because neural tube closes before pregnancy is detected
When should women start taking an iron supplement? Why?
During the 2nd and 3rd trimesters to support the increase in BV, placenta, and fetus
How can black tea affect absorption?
It can inhibit absorption
What can increase iron absorption? 3 things
- Fruits
- Veggies
- Vitamin C
How much folate does the liver store?
Half the folate in the body, which constitutes 30-70x the daily requirement)
