THE EFFECT OF COW AND SOY MILK CONSUMPTION ON CALCIUM LEVELS OF WISTAR RAT TEETH

Background: Complementary food (MPASI) is the main food after the child weans from exclusive breastfeeding. One of the main sources of complementary food is milk. Most children are fed with cow’s milk, but since some children are lactose intolerant, they will be recommended to consume soy milk. However, soy milk and cow’s milk are known to have different amount of calcium as one of the key nutrients for tooth growth and development. The purpose of this study was to compare the effect of cow’s milk and soy milk consumption on the calcium concentration of Wistar rat teeth. Method: Subjects were 27 male Wistar rats aged 1 month old divided into 3 groups, equally with 9 rats in each: groups that consumed cow’s milk, soy milk, and control group. The group consuming Cow and soy milk was fed 2 times a day, in the morning and evening for 28 days. Each subject was then euthanized and their mandibular right incisor was taken at the end of the treatment to measure calcium concentration by atomic absorption spectrophotometry. Result: The results of the one way ANOVA test showed that there were significant differences (p <0.05) in the calcium concentration of incisors in the teeth of rat consuming cow’s milk, soy milk, and control group. Hence, it can be concluded that the consumption of cow’s milk and soy milk has an effect on the calcium concentration of Wistar rat teeth. Conclusion: Calcium concentration of Wistar rat teeth that consume cow’s milk is higher than those that consume soy milk. milk. The main components of milk are protein, fat, sugar (lactose), minerals, and water. Cow’s milk is a very good source of iodine, calcium, vitamin D, riboflavin, and phosphorus. One glass of cow’s milk will meet 50% of the child’s daily calcium needs. The interaction between calcium, lactose and vitamin D present in cow’s milk provides favorable conditions for the absorption of calcium by the body.


INTRODUCTION
Children aged 6-24 months are fed with complementary foods in addition to breast milk (MPASI) to meet their increasing nutritional needs.
Milk, especially cow's milk, is the main source of complementary foods. 1 Milk consumption is of necessity because it contains essential nutrients for growth and development and maintenance of the body. 2 However, lactose intolerance is mostly the main reason for a child to avoid consuming cow's milk. 3 The main components of milk are protein, fat, sugar (lactose), minerals, and water. Cow's milk is a very good source of iodine, calcium, vitamin D, riboflavin, and phosphorus. One glass of cow's milk will meet 50% of the child's daily calcium needs. The interaction between calcium, lactose and vitamin D present in cow's milk provides favorable conditions for the absorption of calcium by the body. 4 One of the main alternative intakes to substitute cow's milk is soy milk. Soy milk is a highly nutritious drink, especially due to its protein content. 2 One of the advantages of soy milk is that it is consumable for people with lactose intolerants. 5 The only drawback of soy milk is the lack of calcium amount of only about a quarter of the calcium content of cow's milk. 3 Calcium is one of the most essential nutrients for tooth growth and development. 6 at the time of tooth eruption, the enamel mineralization process is yet to complete and thus will continue for approximately 2 to 3 years after the tooth eruption. 7 Foods that contain digested calcium will enter the intestine and some of the calcium content in these foods will be absorbed by the intestine. The calcium content absorbed by the intestines will get into the bloodstream. 8 then, blood will distribute calcium throughout the body, through cells, saliva, bones and kidneys. 9 the amount of calcium distributed to saliva will be used for the tooth remineralization process. 10 The albino rat (Rattus norvegicus) is the most commonly used animal model in biomedical research.
The fact that this animal can represent the biological system of mammals makes it a suitable animal model in pre-clinical studies. 11 The aim of this study was to compare the effect of cow's milk and soy milk consumption on the calcium level of Wistar rat tooth crowns.

RESEARCH METHOD
This study was approved by the Ethics Committee, The rats had previously been weaned for 21 days then adapted in the rat cage for 1 week to adjust to the cage conditions. Twenty seven rats were randomly divided into 3 groups of equally 9 rats for each. The rats in group I were fed with cow's milk twice a day, those in group II were provided with soy milk twice a day, while those in group III as the control group were provided with aquades twice a day.
The dose of administration was determined by converting the human dose to the dose of animal models. Cow's milk was administered at a dose of 0.003456 g powder/g BW in 0.0216 ml water/g BW of water per 1 serving of drink, and soy milk was provided at a dose of 0.003456 g powder/g BW in 0.0216 ml water/g BW water per 1 serving of drink.
The control group was administered with distilled water. Feeding was carried out for 28 days.
After 28 days of treatment, each rat was euthanized with an overdose ketamine. The lower jaw was removed and then separated and cleaned. The caries-free mandibular right incisor was separated from the bone. The calcium level of the teeth that were separated from the bone was then measured by the Atomic Absorption Spectrophotometry (AAS) method. Afterwards, the results were processed by one way ANOVA test.  Table 2. Table 2 depicts the significant difference between the calcium levels of the group consuming cow's milk and the group consuming soy milk, with a significance value (p) of 0.038 (p <0.05). There were significant differences between the group consuming cow's milk and the control group with a significance value (p) of 0.000 (p <0.05). There were also significant differences between the group consuming soy milk and the control group with a significance value (p) of 0.041 (p <0.05). Another possibility is because the calcium in soy milk will form a calcium oxalate and calcium phytate complex. Oxalates and phytates will bind minerals, thereby reducing their solubility and bioavailability. 18 The low solubility level will makes it difficult for Ca 2 + ions to break down so that Ca 2 + ions will be impeded from getting into enamel porosity.

RESULT
Cow's milk does not contain oxalates and phytates, and thus Ca 2+ ions diffuse more easily into the enamel surface than soy milk.
The results of this study are in line with those revealed by Heaney et al. (2000), who examined the bioavailability of calcium in cow's milk and soy milk. It was found that the body can better absorb calcium from cow's milk than that of soy milk. 19

CONCLUSION
The calcium level of Wistar rats' teeth that consumed cow's milk was higher than those that consumed soy milk.