Chapter 14
Manganese Usage in Humans as Affected by Use of Calcium Supplements Susan D. McDermott and Constance Kies
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Department of Human Nutrition and Food Service Management, University of Nebraska, Lincoln, NE 68583
Calcium has long been implicated as a dietary factor which inhibits the absorption of manganese. Since manganese is better absorbed in the oxidized (+2) than in the reduced state (+3 or +4), any factor which increases gastrointestinal tract pH (increases alkalinity) would be expected to inhibit manganese utilization. Calcium carbonate, a commonly used antacid by humans as well as a calcium nutrient supplement, has been found to have a greater adverse effect on apparent manganese absorption in humans than does milk. Manganese can exist i n several d i f f e r e n t oxidation states including I, I I , I I I , IV, VI and VII although the most stable s a l t s are those i n the oxidation states I I , IV, VI and VII (_1). Although research on manganese needs of humans i s very l i m i t e d , manganese as a nutrient requirement of plants and factors a f f e c t i n g manganese u t i l i z a t i o n of s o i l manganese by plans has received extensive invest i g a t i o n (1). Total manganese i s generally accepted as being a poor predictor of manganese e x t r a c t a b i l i t y (or a v a i l a b i l i t y ) from s o i l to the plant. One of the most important agronomic c h a r a c t e r i s t i c s a f f e c t i n g manganese e x t r a c t a b i l i t y i s that of s o i l pH. As pH of s o i l s r i s e (as may occur with addition of lime-calcium oxide to s o i l s ) , o x i d a t i o n of manganese II to manganese III and IV i s favored which reduces the s o l u b i l i t y of manganese and, consequently, i t s a v a i l a b i l i t y to plants. Conversely, manganese t o x i c i t y i n plants i s usually found i n acid s o i l s with pH lower than 5.5. Manganese i n the human i s also thought to be absorbed maximally in the duodenum i n the II valence state. Therefore, as with manganese uptake by plants, the pH of the upper g a s t r o - i n t e s t i n a l tract might be expected to be of importance i n the absorption of manganese by the human. Calcium carbonate preparations for many years have been used by humans i n large amounts on a s e l f - p r e s c r i p t i o n basis or as recommended by physicians i n control or treatment of upper gastroi n t e s t i n a l d i s t r e s s conditions which are thought to be related to gastric acid production. These include dyspepsia, peptic u l c e r s , 0097-6156/87/0354-0146S06.00/0 © 1987 American Chemical Society
In Nutritional Bioavailability of Manganese; Kies, Constance; ACS Symposium Series; American Chemical Society: Washington, DC, 1987.
Downloaded by UNIV OF CALIFORNIA SAN DIEGO on February 12, 2016 | http://pubs.acs.org Publication Date: October 5, 1987 | doi: 10.1021/bk-1987-0354.ch014
14.
McDERMOTT AND KIES
Manganese
Use and Calcium
Supplements
147
g a s t r i t i s , e s o p h a g a t i t u s and h i a t a l h e r n i a . A n t a c i d c a l c i u m carbona t e p r o d u c t s a r e a v a i l a b l e i n s e v e r a l forms i n c l u d i n g t a b l e t s , g e l a t i n c a p s u l e s , chewable w a f e r s , gum, and c a r a m e l s ; hence, c a l c i u m r e l e a s e from t h e s e p r o d u c t s designed t o i n c r e a s e pH (lower a c i d i t y ) i n the g a s t r o - i n t e s t i n a l t r a c t would be expected t o v a r y w i t h t i m e . Recent concern r e l a t i v e t o the h i g h i n c i d e n c e o f o s t e o p o r o s i s i n e l d e r l y , female, Americans has r e s u l t e d i n i n c r e a s e d usage o f c a l c i u m supplements. C a l c i u m carbonate c o n t a i n s more c a l c i u m per weight u n i t o f the s a l t than does c a l c i u m phosphate, c a l c i u m l a c t a t e o r c a l c i u m g l u c o n a t e ; hence, e i t h e r c a l c i u m carbonate o r one o f t h e c a l c i u m carbonate forms such as o y s t e r s h e l l s o r d o l o m i t e i s most o f t e n the c a l c i u m s a l t c h o i c e f o r u s e i n a supplement s i n c e fewer c a p s u l e s need t o be taken ( 2 ) . S i n c e c a l c i u m carbonate p r e p a r a t i o n s marketed as a n t a c i d s are o f t e n s o l d a t a p r i c e lower than a r e t h o s e c a l c i u m carbonate p r e p a r a t i o n s marketed as c a l c i u m supplements, c a l c i u m a n t a c i d p r e p a r a t i o n s a r e c u r r e n t l y b e i n g used as c a l c i u m supplements. C a l c i u m has l o n g been s u s p e c t e d as a d v e r s e l y a f f e c t i n g t h e b i o a v a i l a b i l i t y o f manganese. E x c e s s i v e i n t a k e s o f c a l c i u m o r phosphorus have been shown t o i n c r e a s e the d a i l y r e q u i r e m e n t s f o r manganese i n swine (3-5) p r o b a b l y due t o decreased a b s o r p t i o n o f t h i s m i n e r a l . However, c o m p a r a t i v e l y l i t t l e i n f o r m a t i o n i s a v a i l a b l e on the comparative e f f e c t s o f d i f f e r e n t sources o f c a l c i u m on manganese u t i l i z a t i o n i n humans. E f f e c t s o f c a l c i u m phosphate and c a l c i u m l a c t a t e w i t h and w i t h out a s c o r b i c a c i d s u p p l e m e n t a t i o n were examined i n s t u d i e s r e p o r t e d by K o w a l s k i ( 6 ) . C a l c i u m phosphate was found t o have a g r e a t e r nega t i v e e f f e c t on apparent manganese a b s o r p t i o n i n a d u l t humans as judged on p e r c e n t a g e o f d i e t a r y manganese r e c o v e r e d i n f e c e s i n comp a r i s o n t o v a l u e s when c a l c i u m l a c t a t e o r no c a l c i u m supplements were g i v e n (Table I ) . A s c o r b i c a c i d supplements tended t o negate the n e g a t i v e e f f e c t s o f c a l c i u m s u p p l e m e n t a t i o n . Table I .
Parameter
C a l c i u m (Ca) Supplementation and Manganese (Mn) B i o a v a i l a b i l i t y i n Human A d u l t s
_____
Alone
Study 1: ( w i t h 200 mg a s c o r b i c a c i d ) # Subjects 8 Mn i n t a k e , mg/day 2.82 F e c a l Mn, mg/day 1.55 Apparent Mn r e t e n t i o n , mg/day +1.27 % Mn r e t e n t i o n 45.04
b
a
a
+Ca (Ca phosphate) 8 2.82 2.03* +0.79, 28.01
Study 2: ( w i t h no added a s c o r b i c a c i d ) (Ca l a c t a t e ) # Subjects 10 10 Mn i n t a k e , mg/day 4.03 4.03 F e c a l Mn, mg/day 3.81 a Apparent Mn r e t e n t i o n , mg/day +0.12 +0.46^ % Mn r e t e n t i o n 2.98 11.41 Means w i t h d i f f e r e n t l e t t e r s u p e r s c r i p t s are s i g n i f i c a n t l y d i f f e r e n t at p
