Functional Foods: An Overview

Functional foods are a fascinating and rapidly growing area of nutrition, offering health benefits beyond basic sustenance. This overview will explore what functional foods are, how they are classified, their development drivers, and various examples, providing a comprehensive understanding for students.

What Are Functional Foods? A Clear Definition

The term "functional food" originated in Japan in the 1980s, referring to processed foods with added ingredients that support specific body functions in addition to providing nutrients. Generally, a functional food is any healthy food that looks similar to conventional foods, is consumed as part of a regular diet, and is claimed to offer physiological benefits like health-promoting or disease-preventing properties beyond just supplying basic nutrients.

Various definitions exist, but a common thread is the emphasis on benefits beyond basic nutrition. For instance, the International Food Information Council (IFIC) defines them as foods that may provide health benefits beyond basic nutrition. It's important to note that naturally traditional products, like cranberry juice consumed as is for urinary tract health, are generally not classified as functional foods unless their health-contributing ingredient is isolated and added to another food to enhance health.

Terms Related to Functional Foods

The field of functional foods often intersects with other terms, which can sometimes be confusing. Here are some key distinctions:

• Bioactive compounds: Naturally occurring chemical compounds in plants, animals, or marine sources that provide desired health or wellness benefits.
• Dietary supplements: Products with active ingredients added to food or consumed as pills, powders, or liquids. They supplement the diet and do not replace complete meals.
• Functional ingredients: Standardized preparations, fractions, or extracts containing bioactive compounds used by manufacturers in foods.
• Medical foods: Formulated for consumption under physician supervision for specific dietary management of a disease or condition with distinct nutritional requirements.
• Natural health products (NHP): Includes homeopathic preparations, traditional medicines, vitamins, amino acids, essential fatty acids, or other botanical/animal/microorganism-derived substances, often sold in medicinal forms.
• Nutraceutical: Any substance, food, or part of a food that provides medical or health benefits, including disease prevention and treatment. These are food-derived and can be used in forms like pills or liquids.

Classification of Functional Foods

Functional foods can be categorized based on their origin or modification:

• Fortified foods: Products enhanced with ingredients that positively influence health, such as calcium-fortified bread or phytosterol-fortified spreads.
• Liberated foods: Foods modified to counteract anti-nutritional compounds, like those without common food allergens.
• Improved raw materials: Foods where specific components are increased through altered animal feeding (e.g., eggs high in omega-3 fatty acids) or postharvest treatment (e.g., grapes with increased antioxidants via UV irradiation).
• Novel foods: New varieties produced through genetic manipulation or selection, offering improved health benefits, like rice with high iron content.
• Probiotic and Prebiotic foods: This is a significant category:
• Probiotics are live microorganisms that, when consumed in adequate numbers, confer a health benefit to the host (e.g., lactic acid bacteria and bifidobacteria in yogurt).
• Prebiotics are non-digestible food ingredients (like starches, dietary fibers, oligosaccharides) that beneficially affect the host by stimulating the growth and/or activity of beneficial colon bacteria (e.g., probiotic yogurts, prebiotic bread).

Drivers of Functional Food Development

The rise of functional foods is driven by several converging factors:

• Transitional health and urbanization effects.
• Changing demography with an aging population.
• Concerns about food security and loss of traditional food culture.
• Increased awareness of personal health deterioration due to busy lifestyles and poor convenience food choices.
• Competitive food markets and an increased incidence of self-medication.
• Greater information from health authorities and media linking diet and health.
• Significant scientific developments in nutrition research.

Functional Ingredients and Their Benefits

Understanding the relationship between food characteristics and specific health problems is crucial for developing functional foods. Here are examples of functional ingredients and their benefits:

• Alginic acid and xylofucans (from algae): Antiviral activity.
• Anthocyanins, catechins, flavonols (from grapes, berries, eggplant): Antioxidant activity, LDL oxidation inhibition, superoxide scavengers.
• Calcium (from milk): Decreases colon cancer risk.
• Capsaicin (from peppers): Superoxide anion scavenger.
• Carotenoids and lycopene (from tomatoes, carrots, leafy greens): Antioxidant, anti-inflammatory, anti-carcinogenic activity, reduces cardiovascular disease risk.
• Conjugated linoleic acids (CLA) (from lamb, turkey, beef): Reduces breast cancer, atherosclerosis, type 2 diabetes.
• Curcuminoids (from turmeric): Decreases lipid oxidation.
• Daidzein, genistein, isoflavones (from soybean): Inhibits lipid peroxidation, decreases cardiovascular and cancer risks.
• Fiber (soluble and insoluble) (from oats, fortified juice, algae): Reduces total and LDL cholesterol.
• Flavonoids (from celery, parsley, citrus, tea, apples): Antioxidant, antiproliferative, anti-hypertensive, anti-carcinogenic.
• Gallic acid, sulfides, thiols, quercetin, organosulfur compounds (from garlic, onion, broccoli): Decreases blood pressure.
• Lignans (from linseed, fruits, vegetables): Estrogenic effects.
• Phenolic acids and monounsaturated fatty acids (from coffee, tea, olive oil): Anti-inflammatory.
• Prebiotics (from banana, garlic, onions, honey): Stimulate growth of helpful colon bacteria, improving host health.
• Probiotics (from fermented dairy products): Support intestinal tract health, boost immunity.
• Resveratrol, grape polyphenols, ginsenosides, ascorbic acid (from grapes, red wines, ginseng, citrus fruits): Decreases blood pressure, prevents advanced malignancy.
• Sesaminol (from rice oil, sesame seeds): Inhibits LDL oxidation and decreases cancer risk.
• Stilbenes (from grapes, peanuts): Antioxidant, cardioprotective, lifespan extension.
• Tocopherols, ubiquinol, tocotrienols, ω-3 fatty acids, phytosterols (from almonds, nuts, fish oil, various oils): Decreases blood cholesterol, inhibits lipid peroxidation.

Commodity-Based Functional Food Development

Functional food products have primarily been launched in dairy, bakery, confectionery, soft drinks, and baby food sectors. Innovations often target reducing high blood pressure, cholesterol, blood sugar, and osteoporosis.

Dairy-Based Functional Foods

Milk, a rich source of calcium, helps prevent osteoporosis and possibly colon cancer. Beyond basic nutrients, it contains bioactive elements like immunoglobulins, hormones, and peptides. These peptides, derived from milk proteins, can lower blood pressure, combat cardiovascular diseases, and enhance immunity.

Examples of dairy-based functional foods include:

• Calpis Co. (Japan) sour milk with blood pressure-lowering peptides.
• Davisco (USA) hydrolyzed whey protein isolate for blood pressure control (BioZate) and whey protein isolate with glycomacropeptide for blood pressure, dental caries, and infection control (BioPure-GMP).
• DMV International (Netherlands) hydrolysates like C12 and Cysteine peptide for blood pressure reduction and energy boost.
• Lipid Nutrition's Clarinol from yogurt, delivering conjugated linoleic acid to reduce body weight.

Probiotic dairy products, such as those from Danone (Actimel, Activia) and Yakult (Yakult), constitute a major segment, often also containing prebiotics.

Cereal-Based Functional Foods

Cereals provide dietary insoluble fibers (roughage) and water-soluble fibers like β-glucan and arabinoxylan, along with oligosaccharides that promote beneficial physiological effects and stimulate the growth of lactobacilli and bifidobacteria. Barley and oats are rich in β-glucan, known for lowering cholesterol and glycemic index. Extracted β-glucan is incorporated into nutrition bars, cereals, baked products, and yogurts.

Whole processed cereals are also rich in phytochemicals that act as antioxidants, antiproliferatives, and carcinogen detoxifiers. For instance, maize seeds contain xanthophylls that inhibit vessel formation, potentially preventing vascular dysfunction-related diseases. Wheat aleurone-rich foods have been shown to increase fasting plasma betaine and decrease homocysteine and LDL-cholesterol.

Flaxseed-Based Functional Foods

Flaxseed (linseed) is a versatile ingredient rich in proteins, dietary fiber, polysaccharides, polyphenolics, and essential fatty acids, particularly α-linolenic acid (ALA). ALA is known to inhibit cardiovascular disease, inflammation, high blood pressure, cancer, and immune disorders. Phytoestrogens from flaxseed may also benefit menopausal symptoms like osteoporosis. Flaxseed is now incorporated into many cereal-based foods like breads, cereals, and pastas.

Tea-Based Functional Foods

Tea, especially green tea, is a major source of polyphenols, mainly catechins like epigallocatechin gallate (EGCG). These compounds offer antioxidant, anticarcinogenic, antibacterial, antiviral, and blood glucose/lipid controlling properties. Brands like Sunphenon (Taiyo) offer green tea polyphenols, and Mega-T (CCA Industries) provides green tea-based weight loss supplements. Black tea's antioxidant and anti-inflammatory properties are attributed to theaflavins and thearubigins formed from catechin oxidation.

Fruits and Vegetables-Based Functional Foods

Fruits and vegetables are packed with diverse phytochemicals. Berry fruits, for example, are high in polyphenols (anthocyanins, flavonols, catechins) and phenolic acids, offering antioxidant benefits and potential prevention against cardiovascular diseases, cancer, diabetes, and premature aging. Red grapes and red wine contain resveratrol, known for cardioprotective, anti-cancer, and anti-inflammatory effects.

Lycopene, a natural carotenoid antioxidant in red fruits and vegetables (especially tomatoes), protects against oxidative stress, hypertension, and atherosclerosis, and is linked to reduced risks of prostate, lung, and stomach cancer. Innovative uses include fortifying sausages with tomato peel and enriching edible oils with lycopene. Soybeans are concentrated sources of isoflavones (genistein, daidzein), phytoestrogens that may protect against hormone-dependent cancers, cardiovascular diseases, and osteoporosis. Soy protein isolate (SPI) is recognized as safe and can carry a health claim regarding heart disease risk reduction.

Plant sterols and stanols, found in various plant sources, are known to reduce total and LDL-cholesterol, thus lowering the risk of coronary heart disease. Nuts also offer significant antioxidant activity due to their phenolic and flavonoid content, supporting heart health.

Seafood-Based Functional Foods

Seafoods are excellent sources of omega-3 fatty acids (DHA, EPA), antioxidants, and high-quality protein. Marine algae, with its oil and polysaccharides, provides functional ingredients with antihypertensive, antioxidant, antiviral, and anticancer properties. Functional fish with elevated polyunsaturated fatty acids are being developed through specific farming practices. Chitin and chitosan from crustaceans are also used as functional ingredients due to their dietary fiber, antimicrobial, and cholesterol-lowering properties.

Meat-Based Functional Foods

Meat is a source of important nutrients like taurine, L-carnitine, creatine, and CLA. Modifying animal feed, such as adding CLA, can produce meat with reduced atherosclerosis and type 2 diabetes risk. Functional meat products incorporating nuts have been developed to reduce CVD risk. Other additions include fish oil, vegetables, fiber, soy, and natural antioxidant extracts.

Egg-Based Functional Foods

Eggs can be enriched with omega-3 polyunsaturated fatty acids, antioxidants, vitamins D, E, B12, folic acid, and carotenoids. These