When betaine is used as the buffer, the composition comprises about 1% to about 8% by weight betaine, preferably about 3% to about 6% by weight and about 0.2% to about 8% by weight Ca and/or Sr, and preferably about 0.5% to about 4% by weight Ca and/or Sr. When an amino acid such as glycine is used as the buffer, the composition comprises about 1% to about 6% by weight of the amino acid, e.g., gly