Calcium recommendations
Calcium recommendation in a global perspective Leif Hambraeus 24.04.97
Re: Calcium recommendation for nutrition programs in Linley Chiwona Karltun 24.04.97
Re: Calcium recommendation for nutrition programs in developing countries Michael H.N. Golden 24.04.97
Calcium intake : a time bomb ? André Briend 28.04.97
Calcium recommendations in a world perspective Francesco Branca 28.04.97
Calcium recommendation in a global perspective Francesco Branca 28.04.97
Re: Calcium recommendations in a world perspective David Alnwick 28.04.97
calcium deficiency:qinghai/china Colin Mills 05.05.97
calcium deficiency:qinghai/china -Reply Penny Nestel 12.05.97
Calcium intake in Russia and Africa André Briend 28.10.97


 

Date: Thu, 24 Apr 1997 17:23:12 +0200

From: Leif Hambraeus <Leif.Hambraeusatnutrition.uu.se>

Subject: Calcium recommendation in a global perspective

 

The increasing problem of osteoporosis in the industrial countries has led to an intensified debate regarding the relevance of present national (and international) recommendations regarding calcium requirement. Thus the NIH concensus in 1994 recommended an increase up to 1000 mg for adult men and women and 1500 for elderly. Such a high level might be difficult to obtain even in populations where dairy products are representing the major dietary source of calcium.

To my mind it is still difficult to understand to what extent it is a relevant recommendation in a global perspective. Not only is it difficult to obtain such a high calcium intake on a diet free of dairy products, the bioavailability of calcium from vegetable sources may also be different from that of calcium in dairy products. Furthermore what do we know about the ocurrence of osteoporosis in the developing world with an essentially vegetarian diet or mixed diets with low intake of dairy products? And what about the occurrence of osteoporosis in India, where dairy products have a substantial role in the diet, although to a lesser extent than in Western Europe and North America? Or should there really be different recommendations of nutrients for man depending on their staple diets and life style?

When discussing the scientific basis of recommendations of nutrient intakes in a global perspective the values of calcium make me confused. I would appreciate to learn from those

with experience from the nutritional situation in low-income countries as well as in countries where dairy products only constitute a minor portion of the national diet about the incidence of osteoporosis and how they comment the NIH Concensus statement on optimal calcium intake.

 

Leif Hambraeus


Subject: Re: Calcium recommendation for nutrition programs in (fwd)

Date: Fri, 25 Apr 1997 11:20:00 +0100 (BST)

From: Linley Chiwona Karltun

 

I read with interest the explanations that Mike listed regarding the availability of calcium in the diets of people in the developing world. Indeed it is rather rare that one does not eat the bones of the chickens and the bones of other small animal products and not to forget small fishes known as usipa, kapenta, sardellar or by some other name. Infact dried big fishes, especially in East and West Africa, are cooked for rather long periods making the bones soft and thus also ingested. This is not only true for people residing in the developing world but it is also true for African immigrants settled in Europe or the Americas. It is commonplace to see "exotic" foreign shops that import products such as fish from the developing countries and sell them to immigrants that long to consume such foods while living away from home. I often buy and consume such products. In fact, my milk product consumption is all but minimal, whereas the dried fish and bones, and chicken bone consumption is very high. I have also observed that many immigrants prefer to buy and consume meat with bones, cook it until it is very soft and chew on the bones to their heart's content. Surely this must have some implications on the calcium consumption of this particular group. Of course this type of behaviour is not something that one would publicly exhibit when one lives in the "western" world. These practices are very crucial in adhering to and can sometimes determine whether you are part of a group or not.

On the point of geophagia, I couldn't agree more with you. In fact, in Malawi, the soils that are most sought after are the ones that the termites build up. It has a characteristic taste that is very delicious. You will often observe that in a day a person goes around the hut and removes(eats) the termite mounds that have been building up around the poles of the hut.

What this implies I do not know. This practice is not purely restricted to pregnant women. There are other types of soils that are also consumed but this is the favourite in northern Malawi.

Little as I do know about the mechanism of calcium, these observations I believe, might be of significance.

Linley Chiwona-Karltun

 

Linley Chiwona-Karltun

Uppsala University, Department of Nutrition

Dag Hammarskjold vag 21 SWEDEN

S-752 37 UPPSALA SWEDEN

Telephone: + 46 18 182220/182210 Fax: + 46 18 559505


Thu, 24 Apr 1997 18:06:57 +0100 (BST)

Subject: Re: Calcium recommendation for nutrition programs in developing countries

From: "Michael H.N. Golden" <m.goldenatabdn.ac.uk>

 

The very high calcium requirements set by the USA are reflected in the very high levels of calcium fortification in CSB and other relief products originating in the USA. This is turn both increases the cost of the products and unbalances them in terms of the other nutrients.

For example we know that the effect of phytic acid upon zinc and iron availability is dependent upon the calcium available to make the complex - so that high levels of calcium added to the diets could decrease iron and zinc availability. Also food composition tables give TOTAL phosphorus for foods - but much of the PO4 is in the form of phytic acid (which will become available to the plant for growth) but is unavailable to those eating the food. The available calcium:phosphorus ratio is thus disturbed greatly when the diet is supplemented with only calcium.

Why have the USA increased Ca requirements to this extent. It seems to be mainly in an effort to prevent osteoporosis. this is not a topic for this discusion group to get into in a major way - suffice it to say that there are many other factors apart from calcium that have not been properly investigated. Sue New has just done a PhD where she showed that magnseium, potassium and zinc are critical for bone health as well as calcium. And Paul Saltman's group in California has experimentally shown the importance of zinc copper and manganese in maintainance of bone.

There are, in Africa, small pockets of people that are truely calcium deficient. For example, John Pettifor working in Barabwanath Hospital, Joe'burg, describes subjects from a region neer the Mozambique border that have all the signs of rickets from a very low ca intake (about 150mg).

Nevertheless, in general Ann Prentice's work seems to show that there is very little difference in the bone denisty of Gambian's, taking a relatively low Ca intake, from Cambridge women taking a higher intake.

Why should this be?

Several explainations spring to mind that I do not think have been tested in field studies.

First, the influence of FAT in the diet in calcium availabilty has not been examined. Calcium mixed with fatty acids precipitates as "calcium soap" - the scum on the water one sees in hard water areas when you wash - that are insoluble. This presupposes that there are sufficient free-fatty acids formed during gut lipolysis that escape incorporation in a mixed bilesalt micelle to precipitate with the calcium. Nevertheless, the striking differences in fat intake in the USA and the developing world could account for major differences in the availability of calcium.

Second, in my experience nearly all developing country people eat bones - a chicken leg is eaten and only a few "match-sticks" of broken cortical bone are left. When we do a food intake and the person says they ate "chicken" we do not ususally appreciate that they do not leave the bones behind. So that the intake could well be underestimated in some studies. Bone (if you can get it) is a much richer source than milk. I think that is the main reason why man evolved with gastric acid - to digest bone - rather than as an anti-septic.

Third, we have neglected the place of geophagia in mineral nutrition. In Jamaica a survery of 5,000 adults showed that over 20% admitted to regular geophagia. In children it is almost universal - with the problems of helminths and lead poisoning closely related to the amount of soil that was ingested. Geophagia is common throughout the developing world, in many situations, such as pregnancy, special soils are sold in the markets for ingestion. The idea has been that these either represent a response to a deficiency or that they are taken to adsorb food toxins. Neither of these hypotheses fully account for the extent of the geophagia. Perhaps there is a lot of calcium available from these sources that are missed in africal "nutrition" surveys. We should try to understand why these practices have arisen and not just try to stamp them out because the people get worms from eating soil.

In my opinion there are far to many unknowns about the amount, sources, availability and need for calcium in refugee and other poor populations to blindly accept the domestic USA values for the rest of the world. Further, adding large amounts of calcium may affect the metabolism and availability of magnesium, phosphorus, zinc and iron in ways that have not been adequately addressed in the developing world.

Best wishes,

 

Prof. Michael H.N.Golden


Mon, 28 Apr 1997 11:12:19 +0200 (METDST)

From: briendatext.jussieu.fr (Andre' BRIEND)

Subject: Calcium intake : a time bomb ?

 

Low calcium intake are reported all over the world, but this does not seem to ba associated with increased osteoporosis every where. I remember at a meeting a while ago, Ann Prentice mentionend that the incidence of hip fracture in rural Gambia (Keneba) was quite low.

Previous comments in this group may give the reason (bones, local food habits low fat intake, etc...).

I am much more worried about what happens in former USSR and Eastern block countries.

Here we have whole populations with European food habits, used to a high Ca high fat diets who in a few months were swtiched to a high fat, low Ca diet. Most elederly people now cannot purchase milk product any more, which was a very important item in their diet before.

They do not seem to eat bones, nor to rely on geophagia.

I made several trips in former USSR and was suprised to see how little attention this problem received. Of course, low Ca in the diet has no visible consequences in the short term, but I am afraid this may become a time bomb in 10 20 years time.

Does any one know of any progress in this field ?

 

Dr. André Briend


Mon, 28 Apr 1997 18:06:43 +0100 (BST)

From: Francesco Branca <F.Brancaatagora.stm.it>

Subject: Calcium recommendations in a world perspective

 

Calcium intake is a growing concern in former Soviet Union countries. We have information from Azerbaijan showing that the average population intake was 614 mg/person/day in 1985-1995. The lowest calcium intake was observed among children, teenagers, old people, pregnant and breastfeeding women.

In developing countries, although osteoporosis may not be a problem, but hypertension, particularly during pregnancy, may well be. Indeed, I have always though that EPH syndromes are an important cause of maternal mortality. Calcium intake should be evaluated against this outcome.

 

Francesco Branca

Unità di Nutrizione Umana, Istituto Nazionale della Nutrizione

Via Ardeatina, 546, 00179 ROMA

ITALY

 

Ph. +396 5032412, FAX +396 5031592


Mon, 28 Apr 1997 18:24:42 +0200 (ITADST)

From: Francesco Branca <F.Brancaatagora.stm.it>

Subject: Calcium recommendation in a global perspective

 

The topic raised by Leif Hambraeus is very interesting.

Low calcium intake is not just an African prerogative. In the south of Italy calcium consumption during adolescence is below the recommendations, and still fracture rates are lower in the south than in the north. Recent data from the CALEUR study have shown that Italian girls (11-15 years) eating as low as 400 mg/day have the same BMD as girls eating double the amount! The same study has shown that, pooling the data from 5 European countries, there is a weak association between BMD in girls and their calcium intake.

As you are well aware, humans are very good at keeping calcium balance, and the reason why women in the Gambia may do with so little calcium is that they eat less salt and protein than US or European women. Almost certainly physical activity has a greater effect on bone density than calcium intake.

I agree that micronutrients should also be analysed to this regard. In bone cultures of zinc deficient rats, compared to pair-fed, we found that zinc does not only affect growth, but also bone resorption rates, with greater resorption in the zinc deficient. This has also been shown in cell culture studies.

Maybe we should look at calcium balance and bone metabolism in people fed the refugee formulas!

 

Francesco Branca

Unità di Nutrizione Umana, Istituto Nazionale della Nutrizione

Via Ardeatina, 546, 00179 ROMA, ITALY

Ph. +396 5032412, FAX +396 5031592


Date: Mon, 28 Apr 1997 13:41:40 -0400

From: dalnwickathqfaus01.unicef.org (David Alnwick)

Subject: Re: Calcium recommendations in a world perspective

 

Dr Branca's comment that Ca deficiency may cause hypertensive disorders of pregnancy - an important cause of maternal mortality - causes me to enter this interesting debate.

The Nutrition Section in UNICEF has been reviewing what is known about maternal nutrition and subsequent risk of maternal mortality in countries where obsetric care is poor. If fact there is surprisingly little in the literature and little consensus in this area.

UNICEF is a large supplier of iron/folate supplements for use in pregnancy in developing countries, and if something else could be added to pre-natal supplements which could reduce risk of maternal mortality we would be very interested in learning about it.

I got rather interested when I read the meta-analysis of randomised controlled trials by Bucher et al (Effect of Calcium Supplementation on Pregnancy-Induced Hypertension and Preeclampsia) JAMA, APril 19, 1996, vol 275, No.14. which concluded that the odds ratio for pre-eclampsia in women with calcium supplementation compared with placebo was 0.38.

However, in a subsequent conversation with Dr Levine of the NIH, Washington, the principal investigator of a recently completed US multi-centre trial on Ca supplements and pregnancy I was told that these carefully conducted trials showed no relationship at all between Ca intake and hypertensive disorders of pregnancy - even in women who had very low Ca intakes from food. I believe that a summary of preliminary results were presented at the recent FASEB meeting in New Orleans and the formal results will be published later this year.


Date: Tue, 29 Apr 1997 09:59:10 +0200 (METDST)

From: briendatext.jussieu.fr (Andre' BRIEND)

Subject: Calcium intake in Russia and Africa

 

Francesco is right in mentioning physical activity as a major factor influencing Ca balance. I think we should mention genetic factors too. I understand that people of African origin have a better capacity to retain calcium. We should not forget sunshine and vitamin D too.

All this points that former east block countries are at risk, may be more than refugees in Africa.

 

Dr. André Briend


Date: Thu, 08 May 1997 12:43:37 +0100

From: cfmatrri.sari.ac.uk (Colin Mills)

Subject: calcium deficiency:qinghai/china

 

WHO are reviewing controversial estimates of nutrient requirements.

Reports are circulating that,in addition to rickets and iodine deficiency,a deficiency of calcium is causing serious problems in the Qinghai Province of China. Would welcome advice whether any of you have experience of a specific pathology of calcium deficiency in this area.........or are we merely passing judgements on the adequacy of dietary Ca that are based on Western estimates of requirement that, as yet, pay insufficient attention to other dietary variables such as acid/base balance and the content of other micronutrients.

Whether the generally low Ca intakes of E Asiatics are expressed by specific pathological features may well be conditioned by these other variables.

Greetings to all those of you who did so much to help HANSA during the "Jugoslav" crisis.......and best wishes to the HANSA-crew now scattered so widely .

Colin M.


Date: Mon, 12 May 1997 15:56:38 -0400

From: Penny Nestel <penny_nestelatjsi.com>

Subject: calcium deficiency:qinghai/china -Reply

 

Prof Barbara Mawer, Royal Infirmary, Manchester may have some thoughts on this.

fax 161-276-8631 tel 161-274-4833