Calcium beperkt opname van zink nauwelijks

[PowerSupplements]

Het leek me leuk om dit even met jullie te delen (naar aanleiding van een vraag in ons topic).

Journal of Nutrition. 2000;130:1378S-1383S
Dietary Factors Influencing Zinc Absorption
Bo Lönnerdal

Abstract:

Marginal zinc deficiency and suboptimal zinc status have been recognized in many groups of the population in both less developed and industrialized countries. Although the cause in some cases may be inadequate dietary intake of zinc, inhibitors of zinc absorption are most likely the most common causative factor. Phytate, which is present in staple foods like cereals, corn and rice, has a strong negative effect on zinc absorption from composite meals. Inositol hexaphosphates and pentaphosphates are the phytate forms that exert these negative effects, whereas the lower phosphates have no or little effect on zinc absorption. The removal or reduction of phytate by enzyme (phytase) treatment, precipitation methods, germination, fermentation or plant breeding/genetic engineering markedly improves zinc absorption.

Iron can have a negative effect on zinc absorption, if given together in a supplement, whereas no effect is observed when the same amounts are present in a meal as fortificants. Cadmium, which is increasing in the environment, also inhibits zinc absorption.

The amount of protein in a meal has a positive effect on zinc absorption, but individual proteins may act differently; e.g., casein has a modest inhibitory effect of zinc absorption compared with other protein sources. Amino acids, such as histidine and methionine, and other low-molecular-weight ions, such as EDTA and organic acids (e.g., citrate), are known to have a positive effect on zinc absorption and have been used for zinc supplements. Knowledge about dietary factors that inhibit zinc absorption and about ways to overcome or remove these factors is essential when designing strategies to improve the zinc nutrition of vulnerable groups.

Full text: Dietary Factors Influencing Zinc Absorption

In de full text staat de volgende passage over calcium

Calcium. It appears unlikely that calcium per se has a negative effect on zinc absorption. We added calcium to cow’s milk formula to a level of ;1300 mg/L and found no significant difference in zinc absorption from the formula with the regular level of calcium (500 mg/L) through the use of radioisotopes in human adults and paired observations (Lönnerdal et al. 1984). Similarly, Spencer et al. (1984) and Dawson-Hughes et al. (1986) added large amounts of calcium to a meal and found no effect on zinc absorption in human adults. It also appears that the long-term use of calcium supplements has no effect on zinc status; Gambian women who were given 1000 mg calcium/d had plasma zinc concentrations similar to those of unsupplemented women (Yan et al. 1996).
The calcium content of the diet may, however, affect zinc absorption from phytate-containing meals. It has been postulated that the formula [Ca] 3 ([phytate]/[Zn]) ratio can be used as a predictor of zinc bioavailability (Fordyce et al. 1987). The reason for this is that calcium has the propensity to form complexes with phytate and zinc that are insoluble and consequently have an inhibitory effect on zinc absorption.

Melk is dus geen probleem (evenmin als calcium in supplementen). Maar pas op met producten die granen, rijst en mais bevatten.

Kris

[builderB]

godver, rijst krijg je dus ook al kanker van?

j/k bro maar is het gescheiden nemen van rijst en Zink dan een oplossing (sorry, geen tijd om hele artikel te lezen, moet nog eten en heb zo vergadering)

[Angerfist]

net stuk kerel. Kan ik tenminste normaal eten én zma nemen

[Ovide]

Handig stuk ja! Alleen jammer dat toch nog veel voedsel niet goed samen gaat met zma inname producten die granen, rijst en mais bevatten zijn er nog al wat...

[chunky]

neej zeker niet,ik eet altijd kwark met havermout, maar na mijn zma inname. Ongeveer 45 -60 min erna. Maar ja met een beetje geluk is mijn zink dan al op z'n plekje.

[chunky]

in een uur tijd is die shizzle wel al opgenomen toch zeker?

[M@rsel]

Origineel gepost door chunky

in een uur tijd is die shizzle wel al opgenomen toch zeker?

Op nuchtere maag wel ja.

Fytinezuur is gewoon een klotestofje

[Thorium]

er werd eerst gezegd 1 uur na innemen van ZMA mag je alles weer
en 2 uur na het eten van "botsend" voedsel mag je weer ZMA

maar goed dat zeiden ze eerst en toen zeiden ze ook dat ZMA helemaal niet
tegelijk met calcium mocht...

[chunky]

Origineel gepost door M@rsel

Op nuchtere maag wel ja.

Fytinezuur is gewoon een klotestofje

wat is fytinezuur?

[Thorium]

effe gauw van google afgehaald

Granen bevatten fytinezuur, dat een onoplosbare binding vormt met ijzer, zink, magnesium, koper en calcium, waardoor deze mineralen niet of nauwelijks kunnen opgenomen worden. Tarwe bevat het meeste fytinezuur.

[Big Cat]

Phytaten cheleren metalen;, daarom dat ze ook een reputatie hebben als ontgiftende stof. Uiteraard verlagen ze dan ook de absorptie van metalen.

Interessant om weten overigens is dat de aanwezigheid van chloor en bicarbonaat ionen buiten de cel de absorptie van zink ook verhoogt. Intracellulaire magnesium verhoogt dan weer de opname. Bijgevolg is het innemen van magnesium en natrium-bicarbonaat gunstig voor de werking van zink. Daarenboven helpt magnesium tegen krampen, en bicarbonaat tegen spierverzuring. Ze vormen een ideale combinatie.

Ik had er een heel protocol voor uitgewerkt en een supplement er rond gevormd, een van de 4 topsupplementen die ik in ontwikkeling had voor Higher Power Nutrition, maar geen enkele van die producten heeft ooit het daglicht gezien.

Mensen onderschatten zink sterk. Maar mensen die weten hoe ze zink moeten gebruiken denk daar al snel anders over. Het heeft zo'n enorme regulerende werking op plaatselijke IGF's dat het werkelijk superanabole resultaten oplevert als je het goed gebruikt.

Ook omdat dosissen te laag waren. >De officiele toxiciteitsgrens ligt geloof ik nog altijd ergens rond de 50 mg, terwijl al meermaals is aangetoond dat er geen echte toxiciteit optreed in gezonde mensen bij veel hogere dosissen. Enkel wat minder ijzer absorptie, omdat de twee competitie voeren met elkaar over de opname.

[chunky]

Lijkt me dan zeer interessant als je dan misschien iets meer kan vertellen hoe je zink goed gebruikt, daar zullen een hoop mensen in geinteresseerd zijn.

B6 is toch ook nodig voor de opname van zink?

[EricR]

Origineel gepost door Big Cat

Ook omdat dosissen te laag waren. >De officiele toxiciteitsgrens ligt geloof ik nog altijd ergens rond de 50 mg, terwijl al meermaals is aangetoond dat er geen echte toxiciteit optreed in gezonde mensen bij veel hogere dosissen. Enkel wat minder ijzer absorptie, omdat de twee competitie voeren met elkaar over de opname.

Zink is eveneens een koperantagonist. Koper remt overigens niet de opname van zink maar wel andersom dus. Metallothioneine dat in hogere mate wordt gesyntheseerd wordt door een verhoogde zinkinname remt de koperopname.

[rnbflavour]

Origineel gepost door Big Cat

Phytaten cheleren metalen;, daarom dat ze ook een reputatie hebben als ontgiftende stof. Uiteraard verlagen ze dan ook de absorptie van metalen.

Interessant om weten overigens is dat de aanwezigheid van chloor en bicarbonaat ionen buiten de cel de absorptie van zink ook verhoogt. Intracellulaire magnesium verhoogt dan weer de opname. Bijgevolg is het innemen van magnesium en natrium-bicarbonaat gunstig voor de werking van zink. Daarenboven helpt magnesium tegen krampen, en bicarbonaat tegen spierverzuring. Ze vormen een ideale combinatie.

Ik had er een heel protocol voor uitgewerkt en een supplement er rond gevormd, een van de 4 topsupplementen die ik in ontwikkeling had voor Higher Power Nutrition, maar geen enkele van die producten heeft ooit het daglicht gezien.

Mensen onderschatten zink sterk. Maar mensen die weten hoe ze zink moeten gebruiken denk daar al snel anders over. Het heeft zo'n enorme regulerende werking op plaatselijke IGF's dat het werkelijk superanabole resultaten oplevert als je het goed gebruikt.

Ook omdat dosissen te laag waren. >De officiele toxiciteitsgrens ligt geloof ik nog altijd ergens rond de 50 mg, terwijl al meermaals is aangetoond dat er geen echte toxiciteit optreed in gezonde mensen bij veel hogere dosissen. Enkel wat minder ijzer absorptie, omdat de twee competitie voeren met elkaar over de opname.

waarom hebben die producten het daglicht niet gezien dan?

en zou je dan wat meer informatie kunnen geven hoe we zink etc goed kunnen supplementeren?

[rnbflavour]

trouwens mijn lieve dietistjes op mijn studie voeding en dietetiek zeggen dat calcium en magnesium juist elkaars opname verslechteren

[Marijn]

Origineel gepost door rnbflavour

trouwens mijn lieve dietistjes op mijn studie voeding en dietetiek zeggen dat calcium en magnesium juist elkaars opname verslechteren

Leraren houden vaak niet de nieuwe onderzoeken bij en doen alles volgens het oude boekje.
Ik weet ook dingen beter dan mijn fitnessleraar, maar hij geeft toch nooit zijn ongelijk toe dus daar ga ik geen energie in steken.

[rnbflavour]

Origineel gepost door Marijn

Leraren houden vaak niet de nieuwe onderzoeken bij en doen alles volgens het oude boekje.
Ik weet ook dingen beter dan mijn fitnessleraar, maar hij geeft toch nooit zijn ongelijk toe dus daar ga ik geen energie in steken.

ik steek der ook geen energie in hoor
ze leven idd nog bij de dingen van 10 jaar geleden
ma ag wel relaxed zo

fysiologie...hmm ga ik nie heen....
voedingsleer....hmm kijk wel ff op dbb
chemie...hmm gehad op havo hoefk ook nie heen
bio...hmm ken ik ook wel

allen voor psychologie en me projecten ga ik naar school
wel relaxed zo

[Marijn]

Origineel gepost door rnbflavour

ik steek der ook geen energie in hoor
ze leven idd nog bij de dingen van 10 jaar geleden
ma ag wel relaxed zo

fysiologie...hmm ga ik nie heen....
voedingsleer....hmm kijk wel ff op dbb
chemie...hmm gehad op havo hoefk ook nie heen
bio...hmm ken ik ook wel

allen voor psychologie en me projecten ga ik naar school
wel relaxed zo

Geen aanwezigheidsplicht dus?

[rnbflavour]

Origineel gepost door Marijn

Geen aanwezigheidsplicht dus?

ja heel sommige dingen
das wel balen

[Big'r]

Heb eens gekeken naar wat randomized studies ervan zeggen.
Er zijn nogal wat losse variabelen die zink opname beinvloeden, maar eiwitten verhogen de opname.

Zoektermen pubmed --> zinc absorption calcium randomized --> 38 hits --> relevante studies:

Effect of a micronutrient fortificant mixture and 2 amounts of calcium on iron and zinc absorption from a processed food supplement.

BACKGROUND: Iron, zinc, and calcium can interact with each other in a way that inhibits their respective absorption. On the other hand, mineral fortification has been used to improve simultaneous iron and zinc absorption from food supplements. OBJECTIVE: We evaluated the effect of a novel fortificant mixture consisting of NaFeEDTA, zinc methionine, ascorbic acid, and citric acid on iron and zinc absorption from a dry food supplement designed for preschool children. DESIGN: The standard food supplement contained cereal and legume flour, dried milk, and a mixture of micronutrients including ferrous sulfate and zinc sulfate as sources of supplemental iron and zinc, respectively. Standard and novel food products were prepared as porridge with or without the addition of 200 mg Ca as calcium phosphate. Iron absorption and zinc absorption from the food products were evaluated simultaneously in 13 nonpregnant, adult women by extrinsically labeling the products with radioisotopes of iron and zinc and carrying out whole-body counting 7 d after the food products were consumed in random order. RESULTS: The absorption of iron from the NaFeEDTA-containing (novel) food product was 1.7 times that from the ferrous sulfate-containing (standard) product (P = 0.015). There was no significant effect of dietary calcium on iron absorption. Zinc absorption was not associated with the form of zinc consumed, but higher dietary calcium was marginally associated with lower zinc absorption (P = 0.071). CONCLUSIONS: A mixture of fortificants containing NaFeEDTA, zinc sulfate or zinc methionine, ascorbic acid, and citric acid, but without calcium, can improve iron and zinc absorption from food products. A cost-benefit analysis of the novel fortificant mixture needs to be performed.

As is the case for iron, zinc forms insoluble zinc–phytic acid complexes. The food products tested in this study contained 0.5 mmol (306 mg) phytic acid per food product. The mean zinc absorption values of 6–9% in the present study are not different from those reported by Nävert and Sandström (34), who used the same amounts of phytic acid in their study. The negative effect of phytic acid on zinc absorption may sometimes be predicted by the phytic acid:zinc molar ratios of the diet (35). In the present study, the phytic acid:zinc molar ratios for both study food products were 2.7. This molar ratio is considerably lower than the reported values of 15–20 that have been associated with biochemical and in some cases clinical signs of zinc deficiency in humans (36, 37).

We did not observe an effect of the added ascorbic acid and citric acid as enhancers of zinc absorption. This may be due to the possibility that the amount of zinc absorbed from the food product fortified with zinc sulfate was already at the maximal intestinal absorptive capacity. Sandström (38) has shown that when the amount of zinc in a test meal is increased, the maximum amount of zinc absorbed is 18–20 µmol (1.17–1.30 mg). In our study, 6.6% of 174 µmol (11.4 mg) zinc, ie, 11 µmol (0.75 mg), was absorbed from the food product fortified with zinc sulfate, and 7.4% of 174 µmol (11.4 mg) zinc, ie, 13 µmol (0.84 mg), was absorbed from the food product fortified with zinc methionine, ascorbic acid, and citric acid. Thus, it is conceivable that no further improvement in the amount of zinc absorbed was possible.

In some studies, high amounts of calcium were shown to exacerbate the inhibitory effect of phytic acid on zinc absorption in humans by forming a calcium:zinchytic acid complex in the intestine that is even less soluble than are phytic acid and zinc complexes (13, 24). In the present study, zinc absorption from the food product fortified with zinc methionine, ascorbic acid, and citric acid with a low amount of calcium was marginally higher (P = 0.071) than that from the same food product with a high amount of calcium.

As with iron absorption, a previous study found that the inclusion of milk having a high protein content in the study food products had a positive effect on zinc absorption (39). It is possible that proteins and peptides formed complexes with zinc that overcame the inhibitory effect of the addition of 200 mg Ca as calcium phosphate to both food products.
COMPLETE STUDIE: Effect of a micronutrient fortificant mixture and 2 amounts of calcium on iron and zinc absorption from a processed food supplement -- Mendoza et al. 79 (2): 244 -- American Journal of Clinical Nutrition

Zinc balance in adolescent females consuming a low- or high-calcium diet.
There is increasing evidence that calcium intake up to the threshold amount (1480 mg/d) increases bone mass during growth. However, there is concern that such a high calcium intake may interfere with the utilization of other nutrients such as zinc, which is also important for skeletal development. The purpose of our study was to investigate the effect of long-term calcium supplementation on zinc utilization in 26 adolescent females (mean +/- SD age 11.3 +/- 0.5 y) during a 14-d period. Each day subjects consumed a metabolic diet containing 722 mg Ca and 6.3 mg Zn. Participants were randomly assigned to receive either a placebo or a calcium supplement containing 1000 mg supplemental Ca/d as calcium citrate malate. Supplementation began 15 wk before the balance period to allow for adaptation to the greater calcium intake. Mean (+/-SD) zinc balance (0.8 +/- 0.8 compared with 0.3 +/- 1.1 mg/d, P = 0.23), fecal zinc (4.3 +/- 0.6 compared with 4.7 +/- 1.4 mg/d, P = 0.27), urinary zinc (0.4 +/- 0.2 compared with 0.5 +/- 0.1 mg/d, P = 0.55), and net zinc absorption (21% compared with 15%, P = 0.33) were not significantly different between the high- and low-calcium groups. Our results suggest that increasing the recommended dietary allowance of calcium to 1500 mg/d as recommended by the National Institutes of Health consensus panel will not have adverse effects on zinc utilization in adolescent females.

Offtopic, maar toch:

High- versus low-meat diets: effects on zinc absorption, iron status, and calcium, copper, iron, magnesium, manganese, nitrogen, phosphorus, and zinc balance in postmenopausal women.
The effects of three diets--high meat (HM), low meat (LM), or low meat with mineral supplements (LS)--on zinc absorption, elemental balance, and related clinical indexes were investigated in a metabolic study of 14 women aged 51-70 y. The women ate each of the three diets for 7 wk in random order. Lean beef, chicken, ham, and tuna in the HM diet replaced foods with a low mineral content in the LM diet. The LS diet was similar to the HM diet in K, P, Fe, Mg, and Zn contents. Compared with the other diets, the HM diet increased zinc absorption and retention, and slightly increased urinary zinc. Nitrogen and calcium balances and urinary calcium were not different for the HM and LM diets. Iron balance was not different for the HM and LS diets with similar iron content, but the HM diet was unexpectedly associated with lower iron status (higher iron-binding capacity and lower ferritin than LM and LS diets). These results indicate that 0.8 g protein/kg body wt meets protein requirements in older women, and that high meat consumption increases zinc retention without compromising calcium status and may reduce indexes of iron status, in contrast with iron absorption results from studies with radiolabeled test meals.

The effect of calcium carbonate and calcium citrate on the absorption of zinc in healthy female subjects.
OBJECTIVES: The aim of this study was to determine the effect of calcium carbonate and calcium citrate on zinc absorption. DESIGN: The zinc tolerance test (ZTT), which is the plasma zinc response to an oral zinc challenge, was used to quantitate zinc absorption. A physiological test dose of zinc (4.5 mg elemental zinc as 20 mg zinc sulphate) was used. Subjects underwent ZTTs on three separate occasions, each time consuming in random order, either 4.5 mg elemental zinc, zinc with 600 mg elemental calcium as calcium carbonate or zinc with 600 mg elemental calcium as calcium citrate. SETTING: Metabolic ward conditions. SUBJECTS: Nine, free-living, healthy female subjects recruited from the University population. INTERVENTIONS: Blood samples were obtained at 30 min intervals for 4 h postdose. RESULTS: The area under the plasma zinc curve (AUC) (mean +/- SEM) following the coingestion of zinc with calcium carbonate (438.4 +/- 129.0 mumol Zn.min/100 g albumin) and calcium citrate (308.0 +/- 110.5) was significantly lower (P < 0.017) than when zinc was ingested alone (1561.7 +/- 240). Urinary excretion of calcium was significantly higher (P < 0.017) at 4 h after supplementation with calcium citrate (0.83 +/- 0.12 mumol Ca/mumol creatinine) compared with calcium carbonate (0.40 +/- 0.11). CONCLUSIONS: The decrease in zinc absorption following the ingestion of zinc with different forms of calcium suggests that an antagonistic competition occurred between the minerals and that elemental calcium is the inhibiting factor.

Reduction of the phytate content of bran by leavening in bread and its effect on zinc absorption in man.
The effect of leavening of bread containing bran on the phytic acid content and on zinc absorption in man was studied. Twenty breads with leavening times varying from 0 to 120 h were prepared. The breads contained 250 g wheat bran/kg flour. The phytic acid content was determined after baking. The phytic acid content of bread containing bran was reduced to about 40% after 2 h of leavening and to 15% after 2 d. No further decrease was observed. Zn absorption from single meals was determined using a radioisotope technique. Forty-two students volunteered for these studies. They were served a breakfast of milk, butter, bread and 10, 16 or 30 g bran served either raw or baked into the bread with fermentation times of 15 min, 45 min, 3 h or 16 h. One meal contained no bran, but phytate and Zn were added in amounts equivalent to the content of 10 g bran. The amount and percentage of Zn absorbed increased at each bran level as fermentation was prolonged. The percentage of Zn absorbed was reduced by increased bran content in the meal. It is concluded that the fermentation of bread containing bran reduces the phytic acid content and increases Zn absorption from such bread. This may be of importance to people subjected to diets with a high cereal content, especially in combination with a low animal-protein intake.

Zinc absorption from composite meals. II. Influence of the main protein source.
The absorption of zinc in man from composite meals of conventional foods with various main protein sources was measured with a radionuclide technique. The meals were extrinsically labeled with 65Zn and the absorption of zinc was determined from a measurement of the whole-body retention of the isotope about 2 weeks after ingestion of the labeled meal. The meals consisted of a meat patty made from either chicken, beef, or soybeans, and included potatoes, tomatoes, and white bread. For meals based on animal protein a positive correlation was found between zinc absorption and zinc content. When 25% of the animal protein in the chicken meal was replaced by defatted soy flour neither the zinc content nor zinc absorption were significantly influenced. The same substitution in a beef meal resulted in a decrease in zinc content and also a lower zinc absorption. The absorption from a soybean meal did not differ from an animal protein meal with the same zinc content. Lower zinc absorption was found when the calcium content of a soybean meal was increased by the addition of milk. For this study, the total zinc content of the meal was the most important factor influencing the amount of zinc absorbed.

Zinc absorption from composite meals. I. The significance of whest extraction rate, zinc, calcium, and protein content in meals based on bread.
The absorption of zinc in man from composite meals based on bread was measured with a radionuclide technique using 65Zn and whole-body counting. Bread was made up from wheat flour of 100 and 72% extraction rate. A lower absolute amount of zinc was absorbed from the white bread compared to the absorption from the same amount of wholemeal bread. When the two types of bread were enriched with zinc chloride the absorption was higher from the white bread than from the wholemeal bread. Addition of calcium in the form of milk products improved the absorption of zinc from a meal with wholemeal bread. A significant positive correlation was found between zinc absorption and the protein content in meals containing milk, cheese, beef, and egg in various combinations with the wholemeal bread.



NOG WAT INTERESSANTS:

Dietary Factors Influencing Zinc Absorption
Marginal zinc deficiency and suboptimal zinc status have been recognized in many groups of the population in both less developed and industrialized countries. Although the cause in some cases may be inadequate dietary intake of zinc, inhibitors of zinc absorption are most likely the most common causative factor. Phytate, which is present in staple foods like cereals, corn and rice, has a strong negative effect on zinc absorption from composite meals. Inositol hexaphosphates and pentaphosphates are the phytate forms that exert these negative effects, whereas the lower phosphates have no or little effect on z