Fact Sheets

Unpolished rice becomes rancid during storage

Dehusked, unpolished rice grains are covered by the nutrient-rich bran and aleurone layers. Because these layers are rich in lipids (fats), they oxidise rapidly when exposed to air during prolonged storage. This process results in rancid tasting, unpalatable rice grains. Polishing (taking away the outer layers), on the other hand, produces rice grains devoid of the nutrients contained in the aleurone and bran but with stable colour, smell and taste, even after long storage periods.

From bottom left, anti-clockwise: freshly harvested Golden Rice grains; dehusked rice grains; polished rice grains.

Parboiled rice

Parboiling is a process applied to rice to preserve some of the nutrients contained in the outer grain layers (the bran and aleurone layers), which are normally lost during polishing. After a short hot steam treatment part of the nutrients diffuse into the starchy endosperm, thus enhancing the nutritive qualities of the rice. The treatment results in rice that is slightly yellow, hence some parboiled rices carry the name "Golden Rice", which must not be confused with the one produced by genetic modification, as in the project described on this web site.

Because of its golden hue, parboiled rice is called "Golden Rice" in some countries, like the Colombian rice on the picture. While this rice has good nutritional characteristics, mainly due to the presence of soluble vitamins from the B complex, it is different from rice engineered to produce β-carotene in the endosperm.

Clinical Significance of Vitamin A Deficiency

Vitamin A is stored in the liver and deficiency of the vitamin occurs only after prolonged lack of dietary intake. An early symptom of vitamin A deficiency is night blindness. Additional early symptoms include follicular hyperkeratinosis, increased susceptibility to infections and cancer, and anemia &endash;equivalent to iron- deficiency anemia. Prolonged lack of vitamin A leads to deterioration of the eye tissue through progressive keratinization (hardened cell layers) of the cornea, a condition known as xerophthalmia. The increased risk of cancer is thought to be the result of a depletion in vitamin A reserves. β-carotene is a very effective antioxidant and is suspected to reduce the risk of cancers known to be initiated by the production of free radicals. Of particular interest is the potential benefit of increased β-carotene intake to reduce the risk of lung cancer in smokers. However, caution must be exercised when increasing the intake of any of the lipid soluble vitamins. Excess accumulation of vitamin A in the liver can lead to toxicity which manifests itself as bone pain, hepatosplenomegaly (enlarged liver), nausea and diarrhea.

Rice consumption and VAD

The potential impact of Golden Rice depends on rice consumption patterns in a given country. Target countries for Golden Rice deployment have been selected based on dietary patterns by country. It is important to also calculate how much provitamin A is obtained by consumers from other nutrient sources in their diet. This allows us to calculate the gap that must be filled by Golden Rice or other dietary inputs.

The data presented in the tables below are for adults. Children under 6 eat in average about half as much as an adult.

Countries consuming more than 400 grams per person per day

Country	SVAD %	TDCI %	VAID μg/day
Bangladesh	28	71	55.6
Cambodia	42	72	90.3
Indonesia	26	51	289
Lao PDR	42	66	141
Myanmar	35	68	86.8
Viet Nam	12	65	95.8

SVAD, Sub-clinical vitamin A deficiency in children under 6 (UNICEF);
TDCI, total daily rice-based caloric intake (FAO); VAID, vitamin A intake from diet (FAO).

Everybody needs vitamin A but small children are more susceptible to the lack thereof. The recommended daily allowance (RDA) for children 1-3 years of age is 300 μg per day. Supplying half that amount would maintain a healthy vitamin blood level.

Countries consuming approx 200 grams per person per day

Country	SVAD %	TDCI %	VAID µg/day
Brunei		28	216
Burkina Faso	46	6	65.2
China	12	29	288
Cuba		15	125
Guinea	40	33	229
Guinea Bissau	31	42	163
Guyana		31	55.5
India	57	34	124
Korea DPR		34	191
Korea, Rep		30	260
Madagascar	42	48	49.7
Malaysia		30	330
Nepal	33	38	144
Philippines	23	42	106
Senegal	61	30	106
Sierra Leone	47	45	331
Sri Lanka		39	34.9
Suriname		27	63.6
Thailand	22	44	114
Timor-Leste

SVAD, Sub-clinical vitamin A deficiency in children under 6 (UNICEF);
TDCI, total daily rice-based caloric intake (FAO); VAID, vitamin A intake from diet (FAO).

 

Golden Rice flyer by the Golden Rice Humanitarian Board.

Golden Rice fact sheet from the International Rice Research Institute (IRRI), The Philippines here available.