Microencapsulation and Nutritional Supplements

by Lucien Hernandez

Customers are constantly demanding the highest quality and integrity in thenutritional supplements they consume. They want products that taste good andprovide health benefits based on superior performance ingredients. They want toknow that a supplement works and that it contains the level of ingredients shownon the label. For manufacturers, the wellness product industry is fraught withprocessing challenges caused by the inherently sensitive nature of bioactivesubstances. Whether it is the premature reaction of ingredients when combined orthe damaging effects of environmental conditions such as heat, oxygen, moisture,light or pH, the result is products that can taste or smell bad and/or do notdeliver on their therapeutic promise because of reduced bioavailability.

Supplement manufacturers have tried to overcome ingredient limitations in avariety of ways. It is a common practice to add extra excipients to minimizeingredient interactions, but this takes up valuable space in oral dosage formsand only partly solves the problem. Often, overdosing is used to achieve a labelclaim by compensating for expected stability losses, but that can be expensive,arguably harmful and can negatively impact the flavor system. Some ingredients,such as alpha lipoic acid, choline, fish oils and many botanicals may be avoidedentirely because of their taste, odor or stability, which greatly limitsformulation creativity and effectiveness. These issues and others are whymicroencapsulation has emerged as an excellent way to solve many challenges withproblematic ingredient interactions.

Microencapsulation is a technology with a long history in thepharmaceutical, nutritional and food science fields. The latest advances in drugdelivery have their roots in basic microencapsulation. Simply put,microencapsulation is a process whereby small particles, such as bioactivesubstances, are protected from their environment by enveloping them with aprotective barrier coating material. The technology allows a compound to beencapsulated inside a tiny sphere that can be as small as 15 microns, about halfthe thickness of a human hair. Like the pharmaceutical industry, the food andsupplement industries have adopted this technology and adapted it to meet theirspecial needs. Microencapsulated ingredients can be designed to release corebioactives through a variety of mechanisms. Coating materials can be selected todissolve slowly or quickly in stomach acid, or only when a certain pH isreached. Microencapsulation enables formulators to strike the proper balancebetween protection, which means improved bioavailability.

What exactly is bioavailability? Bioavailability is frequently defined as thedegree to which an ingredient becomes available at the site of physiologicalactivity. It is the amount of a compound that is absorbed or available fortherapeutic action, relative to the amount originally provided. In foods andsupplements, very few compounds are directly ingested in their raw form. Theyare typically ingested as part of a complex matrix of nutrients and ingredients.The losses in bioavailability of a compound may start during formulation,continue through product manufacturing, including shelf life instability, andany enteric losses either through premature degradation or through incompletedigestion or release. Most importantly, bioavailability is a function of bothingredient stability and subsequent availability.

Some raw ingredients are especially sensitive to environmental conditions;ascorbic acid is a good example. Losses in potency are exacerbated under complexprocessing conditions such as tableting and extrusion. Not only doesmicroencapsulation improve time zero retention (comparing raw ascorbic versusmicroencapsulated ascorbic immediately after processing), it also significantlyslows degradation in the finished product. In one study, nearly 50 percent ofthe ascorbic acid was lost just from tableting and only about 10 percent wasstill there after six months, whereas nearly 70 percent of the microencapsulatedascorbic acid was still available after six months under similar storageconditions.

Probiotics is another category of very unstable ingredients. Live organismsare very difficult to work with because they are so susceptible to oxidativelosses. Most probiotic products on the shelf today are not viable; the organismsare no longer there in the quantities to be usefulprocessing and storage havekilled them. Fortunately, recent advances in microencapsulation technology haveallowed for excellent stability and viability of live beneficial bacteria, eventhrough food processing and prolonged shelf life. Moreover, microencapsulationcan protect the organisms from low pH in gastric fluids, and can release theorganisms lower in the intestinal tract where they provide the greatest healthbenefit.

Indeed, there are many oxidatively sensitive materials that are veryimportant in human nutrition and health. Omega-3 fatty acids are anotherexample. Here, too, microencapsulation makes it possible to stabilize veryunstable bioactive substances so they can do their job. Taking it yet anotherstep, these oils can be used in many more delivery systems by converting the oilto a free-flowing powder. Marketers are no longer limited in the product formsthey can use to sell these ingredients. They can go beyond softgel capsules totablets, two-piece capsules, nutrient bars and powdered beverages, to name afew.

Microencapsulation is changing the way product developers create new food andsupplement products. Many doors have been opened because microencapsulationtechnology can control, protect and deliver bioactive substances in preciselydefined ways. The ultimate question for producers and consumers remains,however, what is the value of using microencapsulated ingredients to improvestability and subsequent bioavailability? This value proposition can be testedin many ways, some more objective than others. Clearly, using 10 times thestarting dose of raw ascorbic acid in order to have enough to meet label claimsafter six months is a cost that can be compared against the price ofmicroencapsulated ascorbic acid (other issues aside, such as toxicity andregulatory compliance of using so much vitamin C). Avoiding the bad taste of araw ingredient by using a microencapsulated form adds cost to the finishedproduct, but if the product never sells because of its bad taste, it becomesanother product failure. Therefore, what is the cost of product failures andfalse promises? Microencapsulation should be considered when asking thatquestion.

Lucien Hernandez is the business manager for Balchem Corp., a major supplierof encapsulated materials to the nutraceutical, functional food andpharmaceutical industries. He can be contacted at [email protected].