The enrichment of dairy products has evolved over the decades from its origins as a vehicle for addressing widespread vitamin deficiency diseases to addressing the needs of today's better nourished consumers looking for greater functionality and health benefits in their foods and beverages.
Dairy manufacturers are responding to this growing consumer interest and demand by delivering value-added products that address a wide variety of the health benefits considered most important by consumers.
Technological advances in nutrient delivery systems, combined with the hospitable matrix dairy products offer for added ingredients, allows dairy manufacturers to address a larger variety of these health benefits, including eye health.
Healthy vision is among the main concerns of adults in connection with ageing. A global study with over 10,000 consumers found it to be in the top five health issues by which consumers are affected, and the top health concern for which consumers buy nutritional supplements.
The projected number of people with age-related blindness in developed countries is also expected to increase as populations age, fuelling the market for eye-health products.
We tend to take our vision for granted because most of the action takes place behind the scenes. In fact, we actually see with our brain. It is where the information received from the eye is translated.
Light enters the eye through the pupil. The iris adjusts the size of the pupil to adapt to the amount of light available. The eye has a focusing lens—the clear part of the eye behind the iris—that bends light rays to focus images from different distances on the retina.
The lining of the inner surface of the eye is the retina, which is made up of layers of light-sensitive cells. These specialised cells allow vision in bright and dim light and enable us to see colours. The light that reaches the cells in the retina is turned into signals that are transmitted to the brain via the optic nerve, resulting in vision.
At the centre of the retina lies the macula, a highly sensitive yellow spot responsible for detailed central vision. Its yellow colour comes from two plant pigments—lutein and zeaxanthin—which are only obtained through the diet or supplements and are selectively transported to this precise position in the eye. Vision cells in the macula allow us to perform detailed visual tasks such as reading.
Lutein & Zeaxanthin
Lutein and zeaxanthin are bright yellow naturally occurring plant carotenoids and are called ‘the macular pigments’ because of their specialised location. There are only a small number of carotenoids that are taken up by the body and these two are unusual because they are found concentrated in a characteristic yellow spot over a section of the retina that is responsible for central vision—the macula.
Here, they are in the right position to filter out blue light to protect the sensitive vision cells in the macula, and their antioxidant action means they can mop up harmful free-radicals that are generated by normal metabolism in the eye, to continuously guard these delicate cells from oxidative damage.
Furthermore, supplementation studies with the macular pigments showed that they could improve visual function in people with age related macular degeneration (AMD). There is no cure for AMD, but lutein and zeaxanthin may help to reduce the risk of AMD-related vision loss as we age.
Vitamin A is an essential part of vision. A form of vitamin A is bound to the vision photoreceptor cells on the retina. The chemical changes that occur to this form of vitamin A when light enters the eye are the basis of how vision works.
The first signs of vitamin A deficiency include night blindness, and persistent deficiency can result in total vision loss. Vitamin A deficiency is still the leading cause of childhood blindness and is a continuing problem in developing countries, including Asia and South America.
Vitamin A deficiency can also be an issue for some sections of the population in developed countries, such as the elderly, and pregnant and lactating women. Supplying an adequate amount of vitamin A or ß-carotene, which is converted to vitamin A in the body, is vital for good vision.
The vitamins folate, B6 and B12 have been shown to reduce the risk of AMD. These vitamins reduce the concentration of homocysteine in the blood, which is a risk factor for diseases of blood vessels, like AMD and others such as stroke. In a recent clinical trial with over 5000 subjects, people who took these vitamins cut their risk of AMD by about 30 percent.
Vitamin C is an important component of eye nutrition. In the eye, vitamin C is highly concentrated in the lens, where it works as an antioxidant. Antioxidants help protect our eyes from damage caused by the unstable molecules known as free radicals, which can interact with and break down healthy tissues.
Numerous scientific studies have linked vitamin C intake and eye health, specifically, higher intakes of vitamin C or the combined intake of antioxidants had long-term protective associations against development of nuclear cataract in an older population.
Vitamin E’s primary role in the body is to act as an antioxidant. Low vitamin E intake levels, which are fairly common, may increase the risk of AMD. Studies have found that when vitamin E is taken as part of an age-related eye disease formula, a reduction in the risk of AMD progression was observed.
ADVANCES IN NUTRIENT DELIVERY SYSTEMS AND DAIRY'S HOSPITABLE MATRIX ALLOW MANUFACTURERS TO ADDRESS MORE HEALTH BENEFITS.
DHA is involved in the development of vision in the first six months of life. As an important component of retinal pigment cells, it is vital to the optimum function of the retina throughout life. Furthermore, a high intake of DHA and EPA is associated with a 40 percent reduction in the risk of AMD. These eye-friendly fats can be formed to only a limited extent in the body, so supplements provide a reliable source, particularly in people whose dietary intakes are also low.
Research suggests an exciting role in diabetics’ eye health for the isoflavone genistein. This compound has been shown to reduce the toxic effects of high glucose concentrations and oxidative stress in eye experiments, offering hope for nutritional solutions to conditions such as the development of cataracts and damage to the retina due to diabetes.
Other recent research has also indicated that genistein could relieve the symptoms of dry eye syndrome. In an animal model mimicking menopause, genistein increased tear production and the density of the cells that provide moisture to the eye surface. This could be beneficial in preventing and treating dry eyes.
Zinc is an important component of antioxidant enzymes. It helps vitamin A in the eye and works together with antioxidants to slow AMD. Selenium is also a component of antioxidant vitamins and is linked to reduced risk of diabetic cataracts.
Dairy products such as milk, yogurt drinks and yogurts are ideal vehicles for eye health concepts. Convenience, taste and healthy nutrient composition of these products fit very well with the eye health benefit.
Dairy products are good sources of protein and carbohydrates. The fat content dairy products can be modified depending on the need of the target groups. Generally, reduced fat or low fat dairy products provide a more balanced macronutrient composition compared to their whole fat variants. Furthermore, dairy products are good sources of calcium, potassium and magnesium.
Fortification of dairy products with eye health micronutrients is very well feasible. All ingredients mentioned in Table 1 can be incorporated into dairy products such as milk, yogurt drinks and yogurts. At least 15 percent of the recommended daily allowance (RDA) of each ingredient should be used per serving in order to achieve meaningful and health beneficial daily dose.
Depending on the product concept, it could also be advisable to include higher levels of the ingredients. For example, small volume yogurt drinks (100 ml) that are consumed once daily with breakfast can contain up to 50 percent of the RDA.
TECHNOLOGICAL ADVANCES IN NUTRIENT FORMS HAVE ALLOWED FOR BETTER ENRICHMENT CAPABILITIES.
Lutein and zeaxanthin are carotenoids which have a characteristic colour. The colour of lutein and zeaxanthin is dependent on their formulations and the concentration used and will range between yellow and orange.
If ß-carotene is used as a plant based source of pro-vitamin A, it also adds colour. Different product formulations of ß-carotene are available with colours varying from yellow to orange to pink to strawberry red. Therefore, the colour of the final dairy product can be modified by varying the concentrations and the product formulation of the carotenoids.
This can help to match colours associated with fruits in the range from yellow to red. Furthermore, since carotenoids are insoluble and not well soluble in fat, it is crucial to use product formulations that display very good dispersion characteristics. This is especially important in low fat or skimmed dairy products.
High quality carotenoid product formulations disperse well in dairy matrices and neither settles at the bottom of the container nor accumulates at the surface. These product formulations also ensure high bioavailability of the carotenoids and, therefore, optimal effects on eye health.
Emulsified forms of Omega-3 fatty acids are the material of choice for fortification of dairy products. For optimal stability and shelf-life of omega-3 fatty acids in dairy products such as milk, several precautions can be implemented during production.
Due to the high air content, the milk should be de-aerated before standardising. It is strongly recommended to add sodium ascorbate (250 mg per l milk) as antioxidants to the milk before heat treatment or as a sterile solution just before filling using an aseptic dosing system.
Any incorporation of air into the milk should be avoided and the centrifugal pumps and connections should be checked whether they are tight. Storage and buffer tanks should be filled from the bottom. The omega-3 fatty acid emulsion can be dosed after pasteurisation and homogenisation in-line into the milk stream if using an aseptic dosing system or can be streamed directly into the balance tank pre-pasteurisation.
As carotenoids and omega-3 fatty acids are sensitive to oxygen, it is recommended to use packaging material with a low oxygen and transmission rate. Light tide packaging will help to avoid off-flavours and colour shifts. If the package has head space, then nitrogen flushing of head space is recommended.
The evolution of dairy enrichment has blossomed from the early stages of addressing chronic vitamin deficiency with a single nutrient in the US to a full spectrum of choices worldwide representing functionalities that are most appealing to modern consumers.
Dairy producers today have the option to customise products to better address the consumer desire to improve health through daily diet. Technological advances in nutrient forms have allowed for better enrichment capabilities and created opportunities to combine these nutrients into more effective consumer products.
This allows producers to not only better serve customer needs, but also the flexibility to effectively differentiate themselves from competitors.
Applying The BrakeManufacturers can apply the ‘ileal brake’ theory in their slimming formulations to increase satiety levels and reduce appetite.
Recent studies have shown that, under normal physiological conditions, undigested nutrients reach the lowest part of the small intestine, the ileum, where they activate the ‘ileal brake’. This exerts a combination of effects influencing the digestive process and ingestive behavior.
When the ileum detects undigested fat, the body interprets this as an indication that the body has had enough food, known as the ‘ileal brake mechanism’. As a result the brain realises that no more food is required and suppresses the hunger signals it would normally send.
The weight management industry’s interest in the ileal brake has been gathering momentum, as it has been shown to reduce food intake and increase satiety levels, and its appetite-reducing effect can be maintained over time.
Various dairy manufacturers have been incorporating satiety-enhancing ingredients in their products to help slimmers regulate their food intake.
While dieting, it is vital to maintain a good nutritional balance, otherwise the deprivation can take its toll on a person’s appearance, energy levels and overall health. These potentially negative side-effects of dieting can be overcome by complementing a food regime with micronutrients.
Customised premixes blend vitamins, minerals and a wide range of functional ingredients that work well individually and in synergy to replenish the nutritional balance promoting overall health and vitality.
Some of these ingredients have been introduced successfully in milk and yogurt based ready-to-drink products in the US, Europe and Asia. Dairy products have become the preferred deliver system for this type of satiety ingredient as they provide an excellent supply of protein and other base nutrients, and the dairy matrix is quite hospitable to the inclusion of these types of functional ingredients.