What affects Calcium absorption?

Updated on 11. Jan 2009

Before I write anything here, it is important to note that a healthy and balanced diet as we know it from our parents and grand parents is normally good enough to take care of any problems and parents of healthy and happy children growing properly need not worry.
Sometimes, if some doubts appear about the child's growth then it is surely good to consult the doctor and clarify things and ask for some good tips on increasing the calcium intake, if required.

I am required to remove some important calcium sources from my son's diet temporarily. Here are some facts I collected subsequently to ensure a good calcium intake despite that:

Calcium Absorption is affected by:

1. Vitamin D: Vitamin D is very important for good calcium absorption. It is the signal for the body to absorb calcium , if absent causes calcium malabsorption. Among children known as Rickets among children and osteomalacia in adults. Apart from being produced by the body from sunlight, some common and good sources of Vitamin D are saltwater fishes (sea fishes) ; milk and milk products; eggs (egg yolk); liver; fortified products - cereals, margarine, vegan milk sources etc.
   
2. Phytates (phytic acid) : reduce calcium absorption by binding to the calcium ions. These are found naturally in plant sources like grains, whole grain breads, (wheat) bran, soy beans (although the calcium is still partially available for absorption by the body - source), soy isolates, nuts and seeds. Phytates can be reduced by cooking, sprouting and fermentation (lactic acid - through naturally occurring yeasts). Some examples of such fermented products are yoghurt, sour /leavened breads, sour dough starters, yeast breads, rice preparations like idlis, dosas uttapams made with fermented/leavened rice. Sprouting is another wonderful way of reducing these toxins.
   
3. Oxalic acid: It reduces calcium absorption by binding to the calcium ions. Found highly in vegetables like spinach, collard greens, sweet potatoes, rhubarb and beans. (check the link to jugalbandi for more infomation that)
   
4. Age: The amount of calcium absorbed by the body decreases with age. This is one of the reasons why increasing the calcium intake after the age 50+ is so important to prevent calcium malnutrition and prevent osteoporosis, a not so uncommon problem among women and men at this age.
   

Calcium excretion (loss) is affected by (source):

1. Sodium (Na⁺ ; the mineral, a constituent of table salt) and proteins in the food increase the loss of calcium. However, if the food high in sodium and proteins also contains calcium, then it could counteract the effect of calcium loss, as this calcium will get used up to prevent further loss.
2. Potassium (Ka⁺ ; the mineral): High potassium diet, like eating more than 7-8 servings of fruits per day, in the presence of high sodium diet can help decrease the calcium loss .
3. Caffeine intake can temporarily increase calcium loss, but it can be easily counteracted by increasing the amount of calcium intake. Do not drink it together with meals.
   

Sources:
Office of Dietary Supplements
AboutCalcium.net
Wikipedia

As a response to a comment, a clarification:
Please note that building of stones to our present scientific knowledge in whichever part of the body is not less frequent among those who eat meat than those who don't. Vegetarians do not have more stones than those who eat meat. It is, however, advised to those who have kidney stones, for example, to avoid eating plant products high in oxalic acid, or also those who have gaut or rheumatoid arthritis. It is usually a genetic predisposition for some.
If you do not agree with the facts given here or believe them not to be true, then you are most welcome to disagree, but then please include a reliable source of your information, or mention it accordingly and please don't claim it to be a fact just because you have been hearing it from a "neighbour", or have some vague information in your mind, it is irresponsible. use this as a chance to check the information you have before you put it here, please.

Another important aspect of calcium uptake is its interference with the intake of other important dietary minerals like Iron, Magnesium, Zinc and Phosphorus (a separate post on this topic will follow).

Other related posts at H&T:
How much calcium does a child need?

Update on 11. Jan 2009:
Just found this very informative page on calcium at Bee and Jai's Jugalbandi:
Calcium Q&A

Carrot, the best way to eat them....

...is with some oil or a type of fat. Give them to kids grated or cut into thin slices.

It is the oils and fats which are necessary for the good pro-vitamin A (β carotene) to be absorbed by our body. Let the children chew the carrots properly as well.

These are three tempting ways that I remember of doing it for the kids:

1. A yoghurt dip: mix some yoghurt (strained, if possible)/curd/low fat- quark with whipped cream or clotted cream (Indian malai), add some salt and pepper or a pinch of ground roasted cumin. Serve with carrots, grated or cut into thin sticks or rings to be eaten as finger food
2. Just sprinkle grated carrots (or in any form) with some edible oil (which has not been heated!), a teaspoon of lemon juice and a pinch of salt and pepper or ground roasted cumin
3. A vinaigrette: mix some olive oil (or oil of choice) with natural white wine vinegar , salt, mustard (optional), roasted ground cumin, pepper or a pinch of chili powder, stir thoroughly with a spoon till you get homogeneous mass and dip your carrots in it, like we did today (see picture above)

We will use the leftover vinaigrette tomorrow, maybe again with carrots or some cucumber and tomatoes.

TIP: try to use as much oils high in unsaturated fatty acids (mono and poly unsaturated), as they contain the types of fatty acids which cannot be produced in our body. For example.

cold pressed rapeseed oil
cold pressed mustard oil
extra virgin olive oil (EVOO)

These oils are not good for deep frying, as they mono and poly unsaturated fatty acids degrade on heating on high temperatures, the reason why one needs to buy these which have been extracted by cold pressing. But, these can still be used for cooking or (stir-) frying or baking

Some examples of oils which should :

1. not be heated (at best to be used cold),
   
2. always kept in the dark,
   
3. in air-tight containers (should not come in contact with too much air - oxidative degradation)
   
4. and at best be used up fast as they are very unstable, being so rich in unsaturated fatty acids which make them so healthy :
   

• walnut oil
• sesame seed oil
• almond oil
• pumpkin seed oil

Some more comparatively stable oils, which are good for deep frying (should not be done too often, of course!):

• peanut oil
• sunflower oil
• coconut oil
• ghee - not a plant oil, but animal fat, but, is also a good substitute. But, one should keep in mind the high amount of saturated fatty acids and cholesterol in it
  

Therefore, deep frying should best be done not more than once a month, or at best even lesser.
Any type of oil should always be stored in airtight containers otherwise it degrades (becomes rancid) and even the comparitively stable ones, once heated on high temperatures, also start to degrade much more and faster, so repeated heating of oil, especially in large gaps of days is not good. Do not store deep fried oil for long, but, either use it as much possible in the next few days or throw it away. Wastage or not, nothing is wrong if it is for your health.
Give me more names of oils if you want to know about them which I have left out. I have only mentioned the most common ones.

How much calcium does a child need?

This is a post which I'm writing more like in a note form, so that I finally am able to publish it.

Hope it is still of help to others too. Please leave your feedback or comments for any other question you think should be answered in this topic or wish to know more. I'll try to include it. Do check the links given at the bottom in this regard. I have tried to keep the list as small as possible and it contains good links to reliable information, which are also the source of information for this post.


Why do children (and adults - to a lesser extent) need calcium?

Required for healthy mental and physical development of the child - by their growing bones and teeth, important for general cellular (body) functioning, especially nerves and muscles, and activating enzymes required by the body to produce energy, and for blood clotting, and many other important body functions.
Long term shortage can lead to rickets among children (osteoporosis among adults-especially 50+).


How much calcium does a child need (a rough estimate)?

Upto 3 years of age: about 500 mg per day calcium - about 1 1/2 - 2 cups milk or plain yoghurt
4 -8 years of age: about 800 mg per day calcium - about 2-3 cups of milk
9-18 years of age: 1,300 mg per day calcium - about 3-4 cups of milk or the equivalent amount of cheese and yoghurt

The calcium in 1 cup of milk = 1 cup of yogurt = 1 and 1/2 ounces of cheese= 2 ounces of processed cheese. 1 ounce = 28 (25-30) g cheese.

For the body to absorb the calcium properly, adequate amounts of Vitamin D is neccsary. A very good source of Vitamin D is the sunlight, which is required by our body to produce vitamin D in our own body.
Good physical activity, like walking, running, jumping, other sports activities which require the legs to carry the body weight, is necessary for children's bones to develop properly and to promote new bone cells to develop and grow.


Food rich in Calcium

Dairy products are supposed to be the best sources of calcium:
Milk, yoghurt and cheese: gouda, chedder, mozarella, ricotta, soft cheese - mould cheese and many others. Cheese is a much more concentrated form of calcium source than milk. Yoghurt is a more easily digestible (proteins) source of calcium than milk. The best option is to include all of them. Cheese also has much lower lactose content than milk or yoghurt, as it has been broken down and used up by microbes present in cheese, which is usually stored for much longer than yoghurt, for example, which is again a better option than milk.

In case of allergies or lactose intolerance or those living on a vegan diet, it can be compensated with many other vegetable sources, beans and fortified products like orange juice fortified with calcium. But in such cases, a doctors advice needs to be taken to see how it can be achieved best.


Calcium rich non-dairy products, some examples:

Tofu (soyabeans)
Soya milk, fortified
Orange juice (packed), fortified
Muesli and cereals, fortified
Green leafy vegetables - like spinach, beet greens and pak choi,
Beans : soya beans- ripe, white beans, baked beans
Crucifers (Brassica spp.): broccoli, brussels sprouts, kale, collard greens, turnip greens, musttard greens, etc.
Other vegetables: Okra
Nuts and seeds: especially sesame seeds, almonds
Grains: amaranth, quinoa

Many common fish varieties, like rainbow trout (cultured), salmon, atlantic sardines

Following is the list of good links to recipes for the above mentioned categories
(I'll update it everytime I find some good information/recipes):

• Beet greens at Madhuram's Egglesscooking.com
• 
  

Update: A good source of information on calcium from the Office of Dietery Suppliments (National Institute of Health), USA.
Sources of information for this post (please check the websites below for more detailed answers to the above questions):
wiki
Keep kids healthy.com
iVillage: toddlers
About.com
Children need calcium...
Parentingideas.org
calcium for children and teens
good sources of calcium for my child
Calcium: The vegetarian resource group - Nutrition

Other related posts:
What affects calcium absorption?

Update on 11. Jan 2009:
Just found this very informative page on calcium at Bee and Jai's Jugalbandi:
Calcium Q&A