Topics in nutrition and food science. Dr M. Altamimi
Characteristics of Modern life • Urbanisation • Ready to eat food, fast food and processed food. • High calories (fat and carbohydrate) low fibre. • Low in vitamins and minerals. • Packaging. Not natural preservation. • Refrigeration and freezing. • Less physical activity.
Office based jobs. • Chronic diseases, obesity etc. • Aging, people live longer.
Diet – together with physical exercise – plays a major role when we try to prevent or postpone the onset of chronic conditions such as the metabolic syndrome. • The food industry has already reacted to this challenge and a large number of products have been either reformulated or re-positioned to meet the current need for healthier foods.
WHO • Chronic diseases are diseases of long duration and generally slow progression. Chronic diseases are by far the leading cause of mortality in the world, representing 63% of all deaths. 36 million people died from chronic disease in 2008.
Noncommunicable diseases • Cardiovascular diseases account for most NCD deaths, or 17 million people annually, followed by cancer (7.6 million), respiratory disease (4.2 million), and diabetes (1.3 million). These four groups of diseases account for around 80% of all NCD deaths, and share four common risk factors: • tobacco use • physical inactivity • the harmful use of alcohol and • poor diets.
Stages of life and R F In the uterus: • intrauterine growth retardation (IUGR); • premature delivery of a normal growth for gestational age fetus • over nutrition in utero • Intergenerational factors.
Infancy: • Retarded growth in infancy can be a reflected in a failure to gain weight and a failure to gain height. Both retarded growth and excessive weight or height gain can be factors in later incidence of chronic disease. Such as CVD • There is increasing evidence that among term and pre-term infants, breastfeeding is associated with significantly lower blood pressure levels in childhood. Consumption of formula instead of breast milk in infancy has also been shown to increase diastolic and mean arterial blood pressure in later life. Obesity (type 1 diabetes, coeliac disease, some childhood cancers, inflammatory bowel disease) have also been associated with infant feeding on breast-milk substitutes and short-term breastfeeding
Childhood • low growth in childhood and an increased risk of CHD has been described, irrespective of size at birth. • Relative weight in adulthood and weight gain have been found to be associated with increased risk of cancer of the breast, colon, rectum, prostate and other sites. • Higher blood pressure in childhood (in combination with other risk factors) causes target organ and anatomical changes that are associated with cardiovascular risk, including reduction in artery elasticity. • High blood pressure in children is strongly associated with obesity,
Most chronic diseases are present at later period of life - the result of interactions between multiple disease processes as well as more general losses in physiological functions (due to risk factors) = lack of oxygen and adapted metabolism.
Angiogenesis • Angiogenesis is a process of new blood vessel growth that occurs in the human body at specific times in development and growth. • Although crucial for embryonic development and wound healing, angiogenesis also contributes to disease, such as in the growth of solid tumors, chronic inflammation, atherosclerosis, ischemia, and diabetic retinopathy.
Inducers • A number of inducers of angiogenesis have been identified, there is an emerging concept that reactive oxygen species (ROS such as ) superoxide anion O2- hydroxyl radical (OH-), lipid radical (LOO-), peroxy radicals (XOO-) and singlet oxygen (O-). Free radicals ROS are products of mitochondrial respiration (energy production).
Dietary sources of ROS • High fat diet and deep fries • High sucrose (or refined carbohydrates )diet • Protein + sugar in high temperature (glycation) • Low fruit and veg. diet • Low vitamin and mineral diet (antioxidant). Life style: stress, pollution, smoking and low activity.
Golden rule • More free radicals = chronic diseases = faster aging. • Less free radicals = healthier body.
How to slow down generation of Free radicals? • Homework.
Comparison B A Distance: 10,000 km Fuel consumption: 50,000 liter Distance: 200, 000 km Fuel consumption: 1000,000 liter Waste? Maintenance? Type of fuel?
The challenges for nutrition in the twenty-first century 1. Application of new scientific knowledge in nutrition. 2. Improved scientific knowledge on diet–disease relationships. 3. Exponential increase of health-care costs. 4. Increase in life expectancy. 5. Consumer awareness of nutrition and health relationships. 6. Progress in food technology.
Functional foods History Japan: 1940-1950: economical food with minimal nutrients. 1950-1970: safe and hygienic food with better taste. 1970- 1980: convenient food. Easy or precooked food. 1980- :Food for specific health use (foshu). 1990 - :Functional food. (project)
The project also proposed for the first time the new concept of “functional food” and defined food functions as primary (nutritional), secondary (sensory) and tertiary (physiological). Food with physiological functions was of particular interest, because such food would be useful for improving the health of the general public
Definition • no simple, universally accepted definition of functional food exists. Examples • food and drink products derived from naturally occurring substances consumed as part of the daily diet and possessing particular physiological benefits when ingested. • food derived from naturally occurring substances that can and should be consumed as part of the daily diet and that serve to regulate or otherwise affect a particular body process when ingested. • food similar in appearance to conventional food, which is consumed as part of a usual diet and has demonstrated physiological benefit and/or reduces the risk of chronic disease beyond basic nutritional functions.
The main aspects of this working definition are: • the food nature of functional food that is not a pill, a capsule or any form of dietary supplement; • the demonstration of the effects to the satisfaction of the scientific community; • the beneficial effects on body functions, beyond adequate nutritional effects, that are relevant to improved state of health and well-being and/or reduction of risk (not prevention) of disease; • the consumption as part of a normal food pattern.
F F Science • By reference to the new concepts in nutrition outlined above, it is the role of functional food science to stimulate research and development of functional foods
Claim= promise of improvement “Disease reduction claims” meaning: consumers have difficulties to differentiate between the terms ‘disease risk reduction’ and ‘prevention of diseases’.
EFFECT OF FOOD PROCESSING ON FUNCTIONALITY OF FOODS In foods containing vastly different phytochemicals, the physiological activity due to food processing may be a result of more than one mechanism. Consequently, there may be a decrease, increase, or a slight change in the content and functionality of phytochemicals. No/slight effect: carotenoids comprising of b-carotene and lycopene are generally stable to heat treatments encountered in blanching, cooking, and pasteurization/sterilization. Interactions between polyphenols and ascorbic acid may slow the degradation of the latter during storage.
Decrease in content and activity of phytochemicals: a classic example is that of the “technological indicator,” ascorbic acid, which is by far the most sensitive nutrient, and can be damaged during most treatments. Chemical and/or enzymatic oxidations are reported to decrease the antioxidant efficacy of polyphenolics, while leaching into the cooking water is mainly responsible for loss of folates.
Heat processing of Brassica vegetables of the Cruciferae family greatly reduces their functionality . Manufacture of black tea causes a higher degree of enzymatic aerobic oxidation of flavonoids, resulting in lower antioxidant activity. Some processing operations such as peeling and juice clarification can remove the polyphenolics .
Increase in content and activity of phytochemicals: partially oxidized polyphenolics that result during food processing, have been recently shown to exhibit higher antioxidant activity than the corresponding non-oxidized forms, due to increased ability to donate a hydrogen atom A moderate increase in carotenoid bioavailability and enhanced phytochemical nutrient function in cereal processing
Examples of functional ingredients Vitamin antioxidant & mineral premixes; tomato powder, garlic powder, onion powder, spice mixes; amino acids, chitosan; Omega-3-fatty acids (fish and flax seed); whey protein powder; Guarana extract, G. bilobaextract, ginseng extract, rosemary probiotics; natural antioxidants (from tea); “shield” liquid antioxidants; vegetable peptones;
essential fatty acids concentrates; performance proteins; natural fruit based flowering compounds; natural colours; total extracts of medicinal plants “antioxidants” soy ingredient, soy proteins, soy protein hydrolysate; soya protein isolate & concentrate; super critical extracts of spices; and herbs; glutamine peptides; lactoferrin, milk calcium; lycopene, garcinia, raw herbs; whey protein concentrate; wheat fiber, b-carotene; A. veragel powder.
OXIDATIVE STRESS AND ROS • Oxidative stress = rusting of tissues. • Oxidative stress is imposed on the body ’ s cells when the level of ROS outweighs the reducing capacity of antioxidant and antioxidative stress mechanisms ROS
Sources of ROS • Endogenous sources of ROS • tissue injury • via auto - oxidation reactions in the presence of transition metal ions. Fe 2 + or Cu + • during cytochrome P450 cycling. • at inflammatory sites by activated and phagocytes.
Exogenous sources of ROS • Exposure to ultraviolet (UV) radiation. • Overexercise. • Extrinsic xenobiotics found in tobacco smoke. • Heavy metals. • Organic pesticides. • Lipid hydroperoxides in particular are potentially toxic products of peroxidized polyunsaturated fatty acids (PUFAs) derived from dietary fats. • Compounds present in foods such as transition metal ions, heme from meats, isoprostanes, additives, lipids,
DEFENSE SYSTEMS Endogenous antioxidants and antioxidative defenses Glutathione ( GSH ): • tripeptide of γ – glutamylcysteinylglycine. • directly scavenge free radicals or act as a substrate. • GSH present in foods and secreted in the bile can contribute to GSH concentrations in the intestinal lumen.
Antioxidative stress enzymes: • glutathione peroxidase (GPx). • glutathione S -transferase ( GST ). • Catalase Additional antioxidants: • uric acid. • bilirubin - bound albumin, and albumin itself. • Histidine - containing peptides such as carnosine. • Melatonin. • Amino acids, peptides, and even proteins. • Se, Zn, Cu, Mn and riboflavin can all have co-factor functions for one of the above enzymes.
Phytochemicals with antioxidant activities • Polyphenols: 5000 polyphenols and over 2000 flavonoids having been identified. Phenolic acids, Flavonoids, Lignans
Amides strong antioxidants: capsaicinoids in chili peppers. • Carotenoids Lycopene, β – carotene, xanthophylls such as zeaxanthin.
Mechanism of action • direct radical scavenging; (2) downregulation of radical production; (3) elimination of radical precursors; (4) metal chelation; (5) Inhibition of xanthineoxidase; (6) elevation of endogenous antioxidants. Curcumin and flavonoids have been shown to upregulate intracellular GSH synthesis and increase antioxidant enzyme activities
METABOLISM AND BIOAVAILABILITY OF FLAVONOIDS • The extent of absorption of dietary polyphenols in the small intestine is relatively small. • Bacterial enzymes may catalyze several reactions. • Anthocyanins were found in the cerebellum, cortex, hippocampus. = important for learning and memory.