0808 Rice as a Source of Nutrition and Health
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Transcript of 0808 Rice as a Source of Nutrition and Health
RICE AS A SOURCE OF NUTRITION AND
HEALTH
Marguerite Uphoff, MD, MPH
IV. International Rice Meeting
Havana, June 2-6-2008
Rice is the staple food for more than half of the world’s population
Worldwide, rice provides 20% of total human energy Rice consumption varies by region -- annual per
capita consumption of rice ranges from 60 kg to 220 kg in Asian countries, to 12 kg per capita in North America
Rice consumption also varies by income -- dependency on rice is very high among poor people, in parts of Asia rice provides 50 to 80% of all the calories of poor households
In Central America and Cuba, rice provides 5 to 10% of total dietary energy
Rice is more than a source of energy
the major source of energy, but also the major source of protein, and a significant source of fiber and of
essential micronutrients
When rice is a large proportion of the diet, and when the diversity of the diet is limited, as is true for many living in poverty, rice is:
How to make rice count for nutrition
1. Use of all of the nutrients that are in the rice grain
2. Choose the most nutritious varieties– traditional cultivars– conventional breeding – transgenic engineering
3. Harness better cultivation techniques to enhance nutritional value
1. Using all the nutrients: Grain composition and nutrition
Hull (Husk)—removed and discarded in initial milling
Bran: Pericarp, Aleurone, Embryo—removed in further milling and polishing
Endosperm: the white rice that remains after milling and polishing.
Milling and polishing:loss of nutritional valueWhite rice – milled and polished grains
– contains about 90-94% carbohydrates– contains 6-10% protein – contains no significant vitamins or minerals
Brown rice – minimally milled grains– retains the bran -- pericarp, aluerone, and
endosperm– contains about 75-85% carbohydrates– richer than white rice in protein, lipids, fiber, and
vitamins and minerals
Bran is the key to improving rice’s contribution to
nutrition and health All rice lipids are in the bran Rice bran oil has some unique qualities
– 80% of the lipids in rice bran are polyunsaturated fatty acids
– High levels of polyunsaturated fatty compounds are effective in lowering blood cholesterol levels.
Even a little Vitamin E is beneficial for health
– Rice bran oil is a rich available source of vitamin E -- which consists of tocopherols and tocotrienols
– Tocotrienols decrease the synthesis of cholesterol by inhibiting the activity of HMG-CoA reductase, an enzyme involved in cholesterol biosynthesis
– Tocotrienols have been shown to decrease LDL – the “bad” cholesterol -- by 42-62% in animal studies -- and in human studies by 20%
Rice bran also has value for its lipid fraction
– Rice bran oil contains linoleic acid, an essential fatty acid that must be obtained from the diet because the human body cannot synthesize it
– Linoleic acid is important for many cell functions but particularly important for the brain’s development.
Brown rice lowers the grain’s glycemic index
Brown rice has a lower glycemic index because it is digested more slowly than white rice – this is important for diabetes– Fat content in the bran slows the emptying
of the stomach and also the hydrolysis and absorption of starch
– Fiber content in the bran slows emptying time of the stomach
Brown rice can help lower blood pressure
– Brown rice diets have been known for many years to be effective in reducing hypertension.
– Rice bran has recently been shown to decrease hypertension via inhibition of an angiotensin-1 converting enyzme (ACE inhibitor).
Brown rice contributes to antioxidants
The micronutrients manganese, selenium and magnesium are found almost entirely in the bran of rice
One cup (195 grams) of cooked brown rice can provide– 66% of the daily requirement of manganese– 27% of the daily requirement of selenium– 20% of the daily requirement of magnesium
These micronutrients facilitate the synthesis of certain antioxidant enzymes that are protective for the prevention of cancer and inflammatory processes, including arteriosclerotic disease
Other benefits of consuming the whole
grain Eating whole grains such as brown rice is
linked in many studies to protection against :– Coronary artery disease and stroke – Obesity– Insulin resistance (pre-diabetes)– Type II diabetes (adult-onset diabetes)– Celiac disease (gluten intolerance)
Intriguing studies Asthma: One Dutch study found that the
probability of having asthma with bronchial hyper-responsiveness was significantly less in children who had a high intake of whole grains
Gastrointestinal cancer: A British study of gastrointestinal adenoma found that daily consumption of a high dose of stabilized rice bran was associated with an average reduction of 51% in the number of precancerous adenomas in the intestinal tract
2. Choosing the most nutritious varieties
Benefits from traditional cultivars– A study of Philippine landraces (traditional
cultivars) demonstrated average lipid content to be significantly higher than in HYVs collected in the same area – 2.1% for HYVs compared with up to 3.2% for some landrace varieties
– Some landraces had a linoleic acid content of almost 1% of the total grain so that 200 grams of such rice could supply half of an adult’s daily requirement
Traditional cultivars and protein quality
Some landraces in the Philippines have protein content up to 14%; one Chinese long-grain rice has been reported with a 16% protein content
Average protein content of HYVs is 6-11% American and Indian rice breeders recently
announced a hybrid with 12.4% protein.
Traditional cultivars and micronutrients
Commercial varieties of rice usually contain about 2 mg/kg of iron
Some selected Philippine varieties contain more than 5 mg/kg of iron
Certain colored traditional rice varieties in Philippines have 63.5 mg/kg iron.
Some highly-colored landraces in Philippines and Malaysia can contribute most, but not all, of a person’s daily requirement of vitamin A precursors
Remember: iron like other nutrients is in bran!
Bio-engineering nutrition
An transgenic rice has been developed which is iron-rich – It has an iron content of 38 mg/kg
– This iron is stored as iron-ferritin in the endosperm
Therefore, it is in principle more bio-available and is not lost with milling
Bio-engineered Iron-Rich Rice
– The grain has been engineered to have lower phytate levels
Phytates interfere with iron absorption
– The grain also has a metallothionein-like protein that enhances iron absorption
– However, field testing and human
absorption studies have yet to be done
Golden Rice Golden Rice is a transgenic engineering
accomplishment that has been heralded in the popular media as a means of combating vitamin A deficiency.
Ingo Potrykus from Zurich and Peter Beyer of Freiburg developed a biosynthetic pathway that expressed beta carotene in the rice endosperm.
The first Golden Rice (GR1) developed in 1999 contained 1.6 micrograms of beta carotene per gram– This was an order of magnitude more than
most rice but still a small contribution toward the daily requirement.
Golden Rice GR2, developed in 2005, produces up to
37 micrograms of beta carotene per gram of milled rice– This amount theoretically could meet the
daily requirement of someone whose primary source of dietary energy was rice.
However, how well the carotenoids in Golden Rice will be converted to vitamin A in the intestinal tract -- and absorbed into the blood stream -- has yet to be studied.
Golden Rice Golden Rice may make a significant
contribution to alleviating vitamin A deficiency diseases
But the contribution of Golden Rice to human nutrition and health will not be available for a number of years
3. Modifying cultivation to improve nutrition
Cultivation practices and environmental circumstances have been shown to affect the total protein content of rice
Some factors that increase the protein content of rice are:
wider spacing border effectsresponse to nitrogen fertilizervarious stresses
Cultivation practices affect the biological value (BV) of the rice protein– BV reflects the completeness of the set of amino
acids that the body needs for protein synthesis A Bulgarian research project demonstrated that
application of nitrogen-phosphorus fertilizer increased yield and total protein– But this protein had a lower biological
value because of the relative decrease in various essential amino acids: Lysine, Arginine, Threonine, Valine, Leucine and Isoleucine – by 5 to 24%
The effect of fertilizer application on amino acid composition of the rice protein varied among the cultivars evaluated
Biological Value of protein
Cultivation affects BV A study in Japan showed that application
of nitrogen fertilizer changed the free amino acid composition of brown rice
The total amount of some free amino acids (glutamic acid, aspartic acid, asparagine, glutamine and alanine) was higher in grain produced without application of nitrogen fertilizer
The BV of rice protein makes a difference
Study of nitrogen balance in poor children in Peru compared high-protein rice (11.4% protein) diet with conventional rice (7.1% protein) diet:– Children on the high-protein rice diet retained
more nitrogen in their bodies than with the lower-protein rice diet, but
– Less nitrogen was retained per gram of ingested N for high-protein rice compared with the lower-protein rice, indicating that the high-protein rice had lower BV
Rice can contribute more to health and nutrition if we:
1. Consume whole grain rice -- do not discard the most nutrient-rich part, the bran!
Rice can contribute more to health and nutrition if we:
2. Utilize the best available varieties in terms of their nutritional value:
Select and protect a biodiverse set of existing cultivars that provide positive nutritional benefit, and
Continue the breeding and
development of promising new cultivars
Rice can contribute more to health and nutrition if we:
3. Learn more about how alternative cultivation practices affect the nutrient qualities of rice, e.g. SICA
References for “Rice as a Source of Nutrition and Health”
Americal Chemical Society (2006, March 3). “How Nice, Brown Rice: Study Shows Rice Bran Lowers Blood Pressure in Rats.” Science Daily. At www.sciencedaily.com/releases/2006/03/060302180051/htm.
American Chemical Society (2008, January 15). New High Protein Rice Strain Developed. Science Daily. Retrieved May 20, 2008, from http:///.sciencedaily.com/releases/2008/01/080114095753.htm
Bienvenido O. Juliano, in collaboration with FAO Rice in human nutrition,Biochemistry Unit,Plant Breeding, Genetics and Biochemistry Division, International Rice Research Institute, Rome, 1993.
Chavan, J.K., Duggal, S.K. (IARI, New Delhi). “Synergistic effect of different pulses on the protein quality of rice.” Journal of the Science of Food and Agriculture Vol. 29, No.3:230-233 (10 May 2006).
Frei, M, Siddhuraju, P, Becker, K. “Studies on the in vitro starch digestibility and the glycemic index of six different indigenous rice cultivars from the Philippines.” Food Chemistry Vol 83: 395-402. (2003)
Frei, M., Becker, K. “Agro-biodiversity in subsistence-oriented farming systems in a Philppine upland region: nutritional considerations.” Biodiversity and Conservation Vol 13: 1591-1610 (2004).
Frei, M., Becker, K. “On Rice, Biodiversity and Nutrients.” Institute of Animal Production in the Tropics and Subtropics, University of Hohenheim, 2004. Paper available at http:www.greenpeace.org/raw/content/usa/reports/rice.
Frei, M., Becker, K. (Universitat Hohenheim, Stuttgart). “Fatty acids and all-trans-b-carotene are correlated in differently colored rice landraces.” Journal of the Science of Food and Agriculture 85: 2380-2384 (2005).
Gipson, Naomi, McClung, Anna. “There is a lot more to that rice grain than you think.” From www.ars.usda.gov/News/docs.htm?dicud=6616
Goya Food Basics. “Rice—Wholesome & Nutritious. at www.goya.com/english/nutrition/basics_rice.htmlGrusak, Michael A. “Golden Rice gets a boost from maize.” Nature Biotechnology. Volume 23, Number 4,
April 2005: 429-430.
References for “Rice as a Source of Nutrition and Health”
Lucca, Paola, Hurrell, Richard, Potrykus, Ingo. “Fighting Iron Defiency Anemia with Iron-Rich Rice.” Journal of the American College of Nutrition, Vol.21, No.3, 184S-190S (2002).
MacLean, Jr., William C., Klein, Gordon L., Lopez de Romana, Guillermo, Massa, Enrique, Graham, George G. “Protein Quality of Conventional and High Protein Rice and Digestibility of Glutinous and non-Glutinous Rice by Preschool Children.” The Journal of Nutrition. 108:1740-1747, 1978.
Masato, Araki.(Fukuoka Agric. Res. Cent), Matsue,Yuji, Kaneko, Akira. “Relation between Nitrogen Fertilizer and Free Amino Acid Composition of Brown Rice.” Japanese Journal of Soil Science and Plant Nutrition. Vol 70: 19-24 (1999).
Mateljan, George. The World’s Healthiest Foods. 1st edition.George Mateljan Foundation 2006.Minhajuddin, Mohammad. “Can Rice Bran Oil Melt Away Cholesterol?” University of Rochester Medical
Center. Science Daily. May 12, 2005. www.sciencwedaily.com/releases/2005/05/050512110703.htmNuffield Council on Bioethics. “The Use of GM Crops in Developing Countries” Case study 4: Improved
micronutrients in rice. 3.46 There are several research projects… www.nuffieldbioethics.org/go/browseablepublications/gmcropsdevcountries/report_143.html - 18k.
Pfeiffer, Wolfgang H., McClafferty, Bonnie. “HarvestPlus: Breeding Crops for Better Nutrition.” Crop Science. 47:s-88-105 (2007).
Sugano, Michihiro, Tsuji, Etsuko. “Rice Bran Oil and Cholesterol Metabolism.” (Kyushu University). Proceedings VIIth Asian Conference of Nutrition: Lipid Symposium Proceedings. The Journal of Nutrition. 1997. 521S-524S.
Swapan Datta, Vilas Parkhi, Mayank Jai, Jing Tan, Niranjan Baisakh, Lina Torrizo, Editha Abrigo, Norman Oliva, Md. Alamgir Hossain, Russel Julian, Anindya Bandyopadhyay, and Karabi Data. “Golden Rice and improvement of human nutrition.” Rice is Life: scientific perspectives for the 21st century. Session 3. Opportunities and challenges of transgenic rice: 99-101.
Todorov, Methodi Todorov. “Rice yield and its biological value of protein fertilized with an increased rate of mineral fertilizers.” Chaiers Options Mediterraneennes, Vol. 15, No. 1: 65-70.” (?date 1991)
References for “Rice as a Source of Nutrition and Health”
Toenniessen, Gary H. “Crop Genetic Improvement for Enhanced Human Nutrition.” (Rockefeller Foundation). Proceedings of the XX International Vitamin A Consultative Group Meeting. The Journal of Nutrition. 2002. 2943S-2946S.
University of Leicester (2007,March 28). Rice Bran Could Reduce Risk Of Intestinal Cancer. Science Daily. Retrieved May 20, 2008, from http://www.sciencedaily.com/releases/2007/03/070327094325.htm
Vitamin A Deficiency-Related Disorders (VADD): The importance of micronutrients.www.goldenrice.org/Content3-Why/why1_vad.html.Well Being. “Rice-based Diets.” At www.faqs.org/nutrition/Pre-Sma/Rice-based-Diets Nutrition and.html.