Enhance the Power of Milk, but WHY?

Calcium Requirement and Accomplishment

Calcium is one of major mineral required by the body, around 1000 mg/day as daily allowance, which varies with the age, sex and condition of body. During pregnancy, lactation, calcium requirement increases.

Fig 1 requirement of Calcium in different age group

Why You Need Clacium? Function of Calcium in Body

A sum of 99% body calcium is utilizing in bone formation, as it presents in bone as calcium phosphate and only 1% are found outside of it, to performed various functions like clotting of blood, maintain blood pressure, essential for impulse conduction synapsis, assists in muscles contractions and sperm to reach to ovum. Calcium is essential component of synaptic conduction of nerve impulse. When impulse reaches at the nerve endings, the message is translated as Ca-gated crystals bulbs, which releases after interaction of Ca ions. However, some workers see beyond this and they have postulated it also help in message conduction on nerve’s length too. It is presumed that Ca⁺⁺ ion gated channels allow the inflow and outflow of sodium and potassium ions.

Sources of Calcium &; Their Bio-availability

There are many sources of calcium, but searching bioavailable calcium is more important task. There are many food sources which are good source of calcium. Milk is one of the best source for Ca as far as bioavailability is concerned and it fulfill more than half of Ca requirement of body, if taken. Besides, milk, various other milk products are also good source of Calcium. Cabbage family vegetables are good sources of calcium as single cup of herbs contains approximately 158 mg of bioavailable calcium. These herbs are collard greens (Brassica oleracea), cabbage, Chinese spinach (Ipomoea aquatica), Pak choy (Brassica rapa chinensis), Broccoli (Brassica oleracea), Turnip greens (Brassica rapa) and Mustard’s leaves (B. comprestis). Among other sources, almonds, sesame seeds, white beans, pinto beans, red beans, whole wheat bread are also good sources for Ca.

 

Fig 2 Graph showing overall Calcium and bio-availability

Chemistry of Calcium Absorption

Out of total intake only 30-80%, calcium is absorbed in small intestinal lumen in upper, middle and distend region in descending order, mainly through active transport, under acidic condition and up to some extent by passive transport. Active transport of calcium absorption is facilitated by the 1, 25 dihydroxy-cholecalciferol, which induced the synthesis of Ca-binding protein. However, rate of production of 1, 25 dihydroxy-cholecalciferol is strictly under control of plasma Calcium level. 

Also, the absorption of calcium ion is also facilitated by the lactose (milk sugar) and protein. Even up to certain extent calcium is also absorbed in colon, under alkaline condition, which is release from plants sources after the process of fermentation (Basu and Donaldson 2003). Due to decreased in receptiveness of intestinal mucosa for serum calcitriol instead of lowering the level of calcitriol, intestinal absorption of Calcium is started declining with age in human (Scopacasa et al. 2004).

Calcium enters intestinal cells at the brush border membrane and is transported through epithelial calcium channels which expression is on the membrane is function of presence of dietary calcium (Van Cromphaut et al. 2001). Inside the cell, Calcium bounded to a vitamin D-dependent calcium-binding protein, from there, they are transported to the circulation by the action of a Ca-ion pumping ATPase. Active transport of calcium ion is modulated according to blood calcium level, (less than 1.1 mmol/L), absorption is faster while (more than 1.3 mmol/L), absorption is reduced. Absorption is also upregulated during pregnancy, lactation and growth.

Passive diffusion also occurs in the small intestine. This mechanism of absorption is non-saturable and is independent of physiological and nutritional status; rather absorption is increased following increased calcium intake.

Fortification of Milk for Calcium, with Vitamin D

It is now practice in US and other western countries to fortified the food substances with vitamins and minerals to enrich them as per body requirement. Likewise, they also add vitamin D to absorb calcium from milk. Now, let’s see the problem in detail. Hear, you will also understand from the graph that why cow milk is preferable to drink.

Fig. 3

Total calcium requirement- 1200 mg/day (taking the maximum limit)

Total amount of calcium present in around 350 mg (250 ml)

Bioavailability of calcium is about 32%

So, total available Calcium would be 112 mg from each serving cup

Now, this added vitamin (fortified) milk will for (350-112=238 mg) of calcium.

Total amount of vitamin D in milk is 98 IU, which is already present in milk

Therefore, a question arises here, is the single glass of milk is enough to supply daily requirement of calcium, and if not, and per say, 3 glasses are enough, even than what is need of additional vitamin D?

However, prior to advice higher dietary intake of calcium, few issues should be under taken under consideration.
·         status of calcium absorption in patient
·         mode of dispensing the additional calcium
·         calcium salt selection
·         why is it required

however, this excess intake shouldn’t be more than 1500 mg/day (Theobald, 2005). There is also some evidence that high intakes of calcium might potentially cause nutrient deficiencies via interference with the absorption of other minerals such as iron, zinc, copper and magnesium. In case of iron, inhibition is observed in short term study on both haem and non-haem iron, about (∼50–60%) by calcium intake (Theobald, 2005).

In case of iron, inhibition is observed in short term study on both haem and non-haem iron, about (∼50–60%) by calcium intake.  With iron, short-term, single meal studies suggest that absorption of is inhibited by calcium in a dose-dependent manner at intakes of calcium between 150 and 300 mg (i.e. well below the RNI).

Milk Supplements and Their Requirement:

On detail comparison and analysis of a milk supplements, showed following ingredients in different amount in 100 g of product, and the same is compared with barley (Fig. 4). 

Fig. 4

If only two components, calcium and vitamin D are considered, for the dietary supply and claimed enhancement in bioavailability point of view, the facts are like this. According to their claim (as per print on pouch of one of milk supplement), each 100-g powder contains calcium -741 mg and vitamin D-4.6 mcg (184 IU). Now if you take 1 teaspoon (0.3oz or 8.5 g of product), it will add 62.985 mg of calcium and 15.4 IU vitamin D. 

Fig. 5

Therefore, if these ratios appeal you, not bad to go for additional milk supplement, but researchers strongly recommend that the use of naturally occurring products are much better than synthetic ones. Moreover, I am not able to understand that if 98 IU of vitamin D is not able to enhances the absorption of calcium in gut than how 15.4 IU shall do so?