Nutrition Lecture: Miscellaneous Minerals

[liveonearth]

MAGNESIUM
cofactor in over 300 rxns
energy production
synthesis of numerous biomolecules
bone structure
cofactor for alkaline phosphatase, essential to bone mineralization
bases for osteoporosis prevention role
ion transport: role in nerve, muscle, heart disorders
magnesium may help with probs in smooth or cardiac muscle
little intervention research on skeletal muscle probs

MAGNESIUM DEFICIENCY
groups at risk
GI dz
kidney dz and diuretic therapies (loose too much)
alcoholics
elderless (consume, absorb less, excrete more)
severe form rare in young, healthy individuals
usu get enough with varied food and tight regulation of excretoin
severe def affects nerve and muscle

MAGNESIUM USES
PMS, menstrual cramps, dysmenorrhea
migraines
for anything involving spasm of smooth muscle
nocturnal leg cramps, pregnancy induced leg cramps (restless legs syndrome?)
no research on traumatic or exercise-related muscle cramps
good for heart arrhythmias (seems to have helped mine!)
CHF, angina, HTN, MI, mitral valve prolapse
gestational HTN
kidney stones (keeps Ca++ from binding oxalate)
osteoporosis
urinary urgency
asthma
diabetes
IV therapy for pre-eclampsia, MI (controversial), asthma

MAGNESIUM RDA
400-420 mg for men
310-320 mg for women
US diets have been inadequate but are improving
multis typically have little
best sources: leafy greens, whole grains, nuts, fortified foods
some in chocolate but he doesn't buy that your body craves magnesium in it
nutrient not stable in food supply
many US adults getting insufficient amounts
simplest: Mg oxide or chloride (not well absorbed in general)
organic: gluconate, citrate, aspartate, aa chlate
**citrate best absorbed (1 study)
epsom salt is a magnesium laxative

MAGNESIUM SAFETY
slowly absorbed due to laxative effect at 400+mg/day
basis for UL of 350 mg/day
don't take more than 200mg at a time
what about sleepiness??
caution with renal impairment: risk of hypotension and cardiac disturbances
if not excreted quickly enough
hypermagnesemia-->severe SEs

MAGNESIUM INTERACTIONS
human studies show no significant antagonism
best to keep total mineral intake below 500mg at a time for best absorption
fiber: effect probably unimportant

ZINC
catalyzes 100 enzymes
structural role: stabilizes prots and membranes: ex: superoxide dismutase
cell regulation: growth and development, immune fx
some growth disorders traceable to zinc def
COPPER: recommended in combination with copper: take too much zinc-->copper deficieny
high dose copper does not affect zinc (not sure this is true, Zn is Tx for Wilson's)
50mg zinc/day or more can reduce copper absorption
need 10x more zinc than copper in diet
IRON: 40mg/day can reduce Zn absorption
incl Zn in pre-natal and long term anemia therapy as preventative
CALCIUM: high intake reduces Zn absorption in postmenopausal women

ZINC DEFICIENCY
where? Africa, SE Asia, parts of Central and South America, most of Asia low level def
Zn follows protein content in food so high prot diet is high zinc
same areas have most growth retardation, zinc is major cause
also diet high in unleavened whole grain bread (high phytates)
at risk: kids growing fast, infants, children, adolescent, pregnant
3 studies giving slow growing kids zinc-->increased growth
at risk: malnourished, GI probs, seniors
at risk: vegans because plant zinc is harder to absorb, need 50% more than RDA
SX: tissue healing, hair, skin, smell, taste
acrodermatitis enteropathica: genetic dz of zinc absorption & transport
many local & system sx, responds to megadose zinc therapy
"worst case of acne I've ever seen" now used as acne tx
RDA vs average western diet: 11 vs 13 mg/day for men, 8 vs 9 for women
sources: flesh, other proteins foods though less available with phytates present
supps: inorganic such as zinc sulfate
**(avoid sulfates in general: SEs in gut)
organic: zinc acetate, gluconate, picolinate
zinc losenges for common cold: deliver zinc directly to cells attacked by virus
blocks binding of virus to cell ???

ZINC SAFETY & USES
COPPER: risk of copper deficiency above 50mg/day zinc
this is basis for UL of r40 mg/day
GI upset above 50 mg/day but mb only for sulfates
GEL: zinc nasal gel for common cold?
also good but zinc ions are toxic to smell receptors
anosmia may result from overuse, mb permanent
he's nervous about these but I've used them and my sniffer works fine
and I haven't had a cold in years
IF DEF THEN RDA WILL TX
kids in developing countries
elderly? conflicting research
LOZENGES: mixed results, look for gluconate, gluconnate glycine, or acetate (best)
**without added citric or tartaric acid, sorbitol or mannitol (all these bind the zinc)
he uses zinc "cold cure" designed by a chemist, zinc, dextrose and peppermint oil
PREGNANCY COMPLICATIONS: read in notes he skipped in lecture