By David Feder, R.D.
Contributing Editor
Beverages targeting specific health issues comprise a rapidly expanding category. Those that target bone health predominantly include vitamin D and calcium. For years, use of these nutrients was limited to dairy-based products and orange juice to avoid problems with solubility, which in turn can negatively affect sensory characteristics. Now, the drive to widen the variety of available calcium and vitamin D ingredients is increasing.
The importance of calcium in the diet can’t be understated, notes Gregory Miller, Ph.D., executive vice president of research, regulatory and scientific affairs, National Dairy Council, Rosemont, IL. When it comes to receiving this key bone nutrient, he notes 9 out of nearly 10 women, and almost two-thirds of men ages 19 and over, fail to meet calcium recommendations. “Among people age 51 and older, less than 15% get the daily calcium recommended,” he says. “Nearly 9 out of 10 teenage girls, and almost 7 out of 10 teenage boys ages 14 to 18, don’t meet daily calcium recommendations. About 30% of kids ages 4 to 8 don’t get the recommended amount of calcium in their diets.”
A study in the July 2009 issue of Journal of Nutrition Education and Behavior (41(4):254-260) revealed a tendency for young people to reduce calcium intake beginning in high school and as they enter their 20s, the age where consumers substitute soft drinks and caffeinated beverages for milk.
While adding calcium to clear juices and carbonated or novelty beverages is one solution, it can result in higher calorie consumption and a combination of pH and phosphoric acid that might contribute to calcium depletion.
The good news is, dairy popularity is growing. “Dairy-based beverages that are currently growing in popularity include milk- and/or yogurt-based smoothies, flavored milk, kefir and drinkable yogurt,” says Miller.
Ingredients for bone bevs
To maintain bone health, adults need 400 IU, or 10 µg, of vitamin D daily. Calcium needs vary from 1,000 mg for men 19 and up to 1,200 for women 19 and up, adding 100 to 200 mg to those numbers for teenagers. Children ages 4 to 8 need 800 mg calcium daily. Older adults from age 51 need 1,200 mg.
Calcium, however, can pose problems in a drink formulation. Solubility is often the primary issue for manufacturers.
“When developing a calcium-fortified food product, the main parameters used to determine the right calcium source are flavor, solubility, bioavailability, mineral content, costs, ease of processing, natural image and stability in application,” says Lee Heaton, business development manager for health and wellness, Purac America Inc., Lincolnshire, IL.
“Soluble sources vary from extremely bitter, such as calcium chloride, to having a neutral taste, such as calcium lactate or calcium lactate gluconate” says Heaton. “Insoluble sources are, in general, not bitter, but give a sandy or gritty feel in the mouth.”
Nissim Guigui, M.Sc., manager, R&D and quality assurance, Gadot Biochemical Ltd./Pharmline Inc., Buffalo Grove, IL, notes: “Solubility is not always a plus, especially in a milk beverage. Free calcium from high solubility in a high-protein beverage will bind with protein, increasing coagulation. This creates problems such as sedimentation, which in turn affects mouthfeel.”
Classification of calcium as organic or inorganic depends on the anion it binds with, explains Guigui. “You can have calcium from milk that is inorganic if it’s bound to an inorganic ion, such as phosphate or carbonate, vs. being bound to an organic anion, such as citrate, gluconate or lactate,” he says.
Whether organic or inorganic, bioavailability is a big concern. “We start by looking at the solubility without giving up bioavailability,” Guigui says, noting that some calcium ingredients are most bioavailable in acidic formulations at around 3 to 3.5 pH, such as orange juice.