Introduction 

Designer food refers to the food that is designed to have some health benefits other than its traditional nutritional value. ‘Designer food’, ‘functional food’ and ‘fortified food’ are synonym, which refers to the food fortified or enriched with nutrient content already present in them or other complementary nutrient. The term was introduced in Japan in 1980s for referring processed food containing nutrient conferring of some additional health benefits apart from its own nutritional value (Arai 1996), whereas in China, designer food (referred to as health foods) is used in their traditional medicine. About 3000 varieties of health foods are available in China and widely accepted among the consumers due to their long history. Health Canada, department of the government of Canada with responsibility for national public health defines functional food as “A functional food is similar in appearance to, or may be, a conventional food that is consumed as part of a usual diet, and is demonstrated to have physiological benefits and/or reduce the risk of chronic disease beyond basic nutritional functions, i.e. they may contain bioactive compounds” (Health Canada 1998). The Institute of Medicine’s Food and Nutrition Board (IOM/ NAS 1994) defined functional foods as “any food or food ingredient that may provide a health benefit beyond the traditional nutrients it contains”. Functional foods included a wide variety of foods and food components believed to improve overall health and wellbeing, reduce the risk of specific diseases, or minimize the effects of other health concerns (IFIC 2011). 

It can be produced by fortification or nutrification of conventional food. Genetically engineered foods containing higher than normal amounts of health promoting nutrients and fermented foods with live cultures are considered functional foods. Infant formula may be the first designer food as it contains nutrients for the development of brain and immune system. The addition of docosahexaenoic acid (DHA) to health drinks for improving brain and visual development, the alteration or reduction of allergenic components in food, the use of probiotics and nucleotides to enhance immune response and sports nutrition are important examples of designer foods. Table 1 summarizes the health benefits of various designer foods. Fermentation is also a form of food modification. Folk medicine in various countries like China, Japan and India has the tradition of using fermented food for its health benefits, which includes red wine, yogurt, tempeh, red yeast rice etc. Global regulatory status on designer foods Most of the countries have most stringent regulations for food manufactured and imported for its sale, which include United States Food and Drug Administration (USFDA) in the USA (Anon 2010), Health Canada for Canada (Health Canada 1998), European Food Safety Authority for European Union (EFSA 2002), The State Food and Drug Administration for China (SFDA), Food Safety and Standards Authority of India (FSSAI) and Ministry of Food Processing Industry (MOFPI) (FSSAI 2006) for India and Ministry of Health, Labour and Welfare for Japan (MHLW). Only Japan is having specific regulatory approval process for designer foods i.e.

 Foods for Specified Health Use (FOSHU) approved from the Japanese Ministry of Health, Labour and Welfare (Arai 1996). Currently, 100 products are licensed as FOSHU foods in Japan. FOSHU approved products should be in the form of ordinary food not pills or sachets and are for regular consumption as a part of the diet. Designer food or functional foods are gaining greater importance in USA due to their role in disease prevention and health promotion. USFDAs Dietary Supplement Health and Education Act of 1994 (DSHEA) regulates only the dietary supplement or dietary ingredient but not designer food but health claims may be made for foods and dietary supplements in accordance with the 1990 Nutrition Labelling and Education Act (NLEA) and the 1994 DSHEA, an amendment to the Food, Drug and Cosmetic Act. The legitimate basis for health claims were expanded in 1997 with the passage of the Food and Drug Administration Modernization Act. Under this act health claims may be approved on the basis of recommendation from certain federal agencies in the Department of Health and Human Services and the Department of Agriculture, and from the National Academy of Sciences or any of its subdivisions (USFDA). According to NLEA health claim represents the relationship between a nutrient and a disease or medical condition that is related to the diet. In Canada there is no specific regulation for neutraceuticals, but the Food and Drugs Act and Regulations regulates the quality and safety of all foods and drugs. 

Under the Act, the “food” includes “any article manufactured, sold or represented for use as food or drink by man, chewing gum and any ingredient that may be mixed with food for any purpose whatever.” As per this regulation currently permit only ‘food as part of healthy eating and claiming that a nutrient or nutritive substance is generally recognized as an aid or factor in maintaining the functions of the body, or necessary for the maintenance of good health and normal growth and development (also known as “biological role claims” and nutrient function claims)’. Because of the dichotomy of designer food between foods and drugs, manufacturers of nutraceuticals and functional foods are left with two choices, either they can market their product without health claims or they have to follow more stringent regulatory requirements necessary for drugs (Food and Drug Regulations). The Europoean regulatory has broad category as nutraceuticals and the definition of a nutraceutical is, “any food or food ingredient which is considered to have a beneficial effect on health”. Nutraceuticals are required to comply with food law but are not under the provision of s130(2) Medicines Act 1968 due to its health claim not medicinal claim. 

The Food Safety Act 1990 (FSA), subsequent primary and secondary legislation and codes of practice ensure that food placed on the market is safe and that any information provided about the product is not misleading. European regulatory includes food for specific health benefit rather than to enhance physiologic function, may include infant formula, processed baby foods (weaning foods), low-calorie foods for weight reduction, high-calorie foods for weight gain, ergogenic foods for athletes, and foods for special medical purposes like the treatment of diabetes or hypertension. India has Food Safety and Standards Act, 2006, Food Safety and Standards Rules, 2011, Food Safety and Standards Regulations, 2011 and the Food Safety and Standards Authority of India (FSSAI), established under the Food Safety and Standards Act, 2006 as a statutory body for laying down science based standards for articles of food and regulating manufacturing, processing, distribution, sale and import of food so as to ensure safe and wholesome food for human consumption. In India, normal food, nutraceuticals, designer food/functional food etc. are not categorized separately (FSSAI 2006).

 A brief account of selected designer foods is given below. Designer eggs Regular intake of well balanced diet plays an important role in maintaining good health. Among various foods, egg is an important and easily available food delivering balanced essential nutrients to the body and egg is the best medium for incorporating health components in it. The designer food approach has been explored widely using egg in providing various essential nutrients to the human body, which are not usually present in required quantity (Sim 1998). Designer egg approach was started in 1934 by Cruickshank, who reported the modification of fatty acid composition in egg yolk by making feed interventions. Omega-3 fatty acids are proved to be beneficial in various disorders such as cardiovascular disease, hypertension, autoimmune, allergic, and neurological disorders and it is also essential for normal functioning of the human physiology not only in normal adult and also in pregnant and lactating women. A diet balanced in omega-3 and omega-6 fatty acids is important during human evolution (Hargis and Van Elswyk 1993; Simopoulos 2000). Dennehy (2011) stated in his review on omega-3 fatty acid that there are sufficient data from randomized controlled trials on omega-3 fatty acids and ginger that their pharmacologic properties, efficacy, and safety data for specific indications in maternal health.

 Omega-3 fatty acids benefit gestation, infant vision, and neurodevelopment and ginger is efficacious for nausea in pregnancy but is limited in its safety data. It is also recommended to take omega-3 fatty acid supplement daily during pregnancy (Abdel-Nour and Ngadi 2011). Gheita et al. (2012) in their study stated that add on supplementation with omega3 fatty acid along with non steroidal anti-inflammatory drugs (NSAIDs) in juvenile idiopathic arthritis was proved to be effective as it reduces the daily requirements of NSAIDs and the risk of related side effects. Sim and Sunwoo (2002) developed designer egg rich in omega-3 fatty acids and antioxidants by feeding hen with flax seed and patented as Professor Sim’s Designer Egg, in which saturated fatty acid in yolk was replaced with 3-poly unsaturated fatty acid (PUFA) i.e. the yolk triglyceride is replaced by linolenic acid and yolk phospholipids are J Food Sci Technol (January–February 2013) 50(1):1–16 3 replaced by longer chain omega-3 fatty acids, such as eicosapentaenoic (EPA), dososapentaenoic and docosahexaenoic (DHA) acids (Jiang et al. 1991). To overcome the instability due to 3-PUFA the authors incorporated natural antioxidants like vitamin E, selenium and carotenoid pigments. Caston and Leeson (1990) also reported that the increase in the concentration of omega-3 fatty acid in hens egg by adding flax seed or fish oil in hens diet. Bourre and Galea (2006) produced designer egg fortified with omega-3 fatty acid by feeding hens with linseed, minerals, vitamins and lutein. 

The nutritional value of 100 g of these eggs contains 6 times more of the omega-3 fatty acid alpha-linolenic acid (ALA), 3 times more DHA, 3 times more vitamin D, 4 times more folic acid, 6 times more vitamin E, 6 times more lutein and zeaxanthine, 2.5 times more iodine and 4 times more selenium. These eggs also contain a little amount of cholesterol and, like standard eggs, are rich in B—complex vitamins and vitamin A, phosphorus and proteins. The consumption of these eggs improved the blood concentration of omega-3 fatty acids, high density lipoprotein (HDL)—cholesterol, low density lipoproteins (LDL)—cholesterol and triglycerides. These omega-3 fatty acids enriched designer eggs showed better stability of PUFA during egg storage and cooking, high availability of such nutrients as vitamin E and carotenoids, which improves antioxidant and omega-3 status of people consuming these eggs (Surai and Sparks 2001). Fortification of omega-3 fatty acid not only increases the health benefits of designer egg but also reduces the cholesterol content of the egg by replacing saturated fatty acid in egg yolk. 

The dietary cholesterol and fatty acids plays an important role in various cardiovascular diseases. The scientific attempt to reduce cholesterol content in diet is the promising approach for the management of cholesterol (Hargis 1988). Designer eggs were also developed by replacing yolk cholesterol with conjugated linoleic acid (CLA). CLA is studied for its various health related properties such as anti-adipogenic, anti-carcinogenic, anti-atherogenic and anti-inflammatory (Magdalena et al. 2008). Raes et al. (2002) produced designer egg enriched with CLA by feeding hens with CLA rich diet and found that adding CLA to layers diets rich in omega-3 fatty acids produces CLA enriched eggs. Cook et al. (2000) had patented a method of production of CLA enriched designer eggs by feeding poultry a diet enriched in CLA. Dietary addition of CLA to hens diet decreased lipid content and concentrations of monounsaturated fatty acids in egg yolk, but increased CLA and saturated FA. CLA supplementation of egg also increased yolk moisture content, firmness and impaired the sensory quality of eggs. Magdalena et al. (2008) studied the anti-cholesterol and antiinflammatory effect of CLA-enriched eggs in animal models. The authors found that CLA-enriched eggs significantly reduce total plasma cholesterol as compared with CLA-supplemented eggs and it also reduces the size of atherosclerotic plaque, number of atherogenic macrophages and increases the area occupied by smooth muscle cells in atherosclerotic. Cholesterol content of the egg yolk can also be reduced by supplementing hen’s feed with chromium at 200–800 ppb concentration (13.9 to 33.7 % reduction) (Anderson et al. 1989; Lien et al. 1996).

 The pharmacological approach was also studied for reducing cholesterol level in egg by administering egg laying hens with cholesterol lowering drugs. US patent was issued to Meier and Wilson (1997) for the method of reducing the cholesterol content of egg by supplementing hen with L-dihydroxyphenylalanine (L-DOPA). Selenium (Se), a micronutrient is essential for preventing cardiac muscle degeneration. Supplementation of Se will enhance Se-specific antioxidant status and improve the development of embryos in gilts (Fortier et al. 2012). Se has an essential role in thyroid hormone metabolism and iodine (I) deficiency (Kandhro et al. 2011). Se supplementation is used globally for preventing and treating muscular dystrophy and other Se deficiency syndromes (Beale et al. 1990). Se deficiency is a global problem, to treat this deficiency regular intake of Se rich food is important. Organic source of Se is better absorbed than inorganic source (Fortier et al. 2012). Compared to plant source, egg and meat are the good source of Se. Recommended daily requirement of Se is 55 μg for human adults (Bennett and Cheng 2010). Regular dietary intake at recommended level may reduce the risk and prevalence of prostate and colon cancer and it also proved to have a role in prevention of cardiovascular diseases through antioxidant property (Navarro-Alarcon and Cabrera-Vique 2008; Bennett and Cheng 2010).