Nutrition and Metabolism Assignment

Combination of food.
Persimmons and Sweet Potato: Will it cause Vitamin A toxicity and a person can get very ill if consume together?
By Wang Wei Ling (1000615133)

Human stomach can normally digest any number of different foods at the same time. Combinations of food mean those foods that are compatible with each other in terms of digestive chemistry. Food combining is based on the theory that different food groups require different digestion times. Correct food combinations are important for proper digestion, utilization and assimulation of the nutrients in our diet. However, incorrect combination of food can lead to some what a disaster. Incorrect combination can lead to stomach pain, diarrhea, dizzy and so on.

Combination of persimmon and sweet potato is an incorrect food combination. Persimmon and sweet potato can normally be found at local stores. Although not much people will have the chance to consume both of these food at the same time, but the risk of it is still exist.


Both of these foods have their own good properties when they are alone. Persimmons are low in calories and fat but it is a rich source of dietary fiber, which is good for the intestinal activity. Persimmons are also famous with their phyto-nutrients flavonoid poly-phenolic antioxidant compound such as catechins and gallocatechins, which normally are found in green tea. Persimmons also contain some anti-tumor compound like betulinic acid and shibuol. Persimmons also play a role as the protective scavengers against oxygen-derived free radicals and reactive oxygen species that act in aging and various disease processes. This is because persimmons contain vitamin A, beta carotene, lycopene, lutein, zeaxanthin and crypotoxanthin which are the antioxidant compounds. Persimmons also rich in vitamin C that can helps the body to develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals. It also has a healthy amount of minerals such as potassium, manganese, copper and phosphorus. Manganese is a cofactor for the enzyme superoxide dismutase, a very powerful free radical scavenger. While copper is a cofactor for many vital enzymes, including cytochrome c-oxidase and superoxide dismutase.


Sweet potato is an excellent source of vitamin A, beta carotene and vitamin C. Beta carotene not only is just the part of carotenoid vitamin family, it is one of the antioxidant compounds. Sweet potato contains vitamin B6 that can reduce the concentration of homocysteine in the blood. Homocystein is an amino acid in blood where when it is at a high concentration, it can lead to higher risk of coronary heart disease, stroke and peripheral vascular disease. Sweet potato also contains a significant amount of dietary fiber that can helps promote the good health of digestive tract. Sweet potato is an excellent source for manganese which is a cofactor for enzymes involved in hydrolysis, phosphorylation, decarboxylation and transamination. Iron and copper are minerals that are essential to immunity, maturation, function and activation of defense mechanisms that can be found in sweet potato too.

Starchy food is advisable to not consume with sweet fruit. This is due to that combination of both these food at the same time might result in stomach acid which will lead to gastric hemorrhage or gastric ulcer. In this case, sweet potato is considers as starchy food while persimmon is in the category of sweet fruit.
When sugar is eaten through mouth, the mouth will be filled by saliva but without the presence of ptyalin, which is an amylase produces by salivary glands. This is because sugar does not undergo digestion process in the mouth and stomach. Thus when starch is disguised with sugar, the taste buds of the mouth are deceived, leads to impaired carbohydrate digestion of starch. When this combination of food travelled to the stomach, sweet potato which is rich in dietary fiber will tends to delay the stomach digestion, resulting the sugar will also gets held in the stomach for a longer period of time. Eventually, this will promotes the fermentation process to happen in the stomach due to improper carbohydrate digestion in previous stage. Simple sugars such as monosaccharide and disaccharides sugars are easily to be fermented compared to polysaccharides which in this case, persimmons are loaded with simple sugars. A compound called as shibuol that can be found in persimmons can also lead to bezoar, which is the hardening of solid food in the stomach that can lead to obstruction in the stomach. Shibuol will actually react with the acid environment of the stomach to form a gooey compound. This will actually worsen the condition in the stomach.

When the fermentation process occurs in the stomach, the bacteria will turn the food into alcohol and acetic acid which will further increase the acidity of stomach. Thus, this may lead to gastric ulcer or gastric hemorrhage. Other than these, the products produced by the fermentation process can also be toxic to the cells and tissues when absorbed by the intestinal villi.
Both sweet potato and persimmon contain high amount of vitamin A, in the form of beta carotene. Is true that excess amount of vitamin A can lead to toxicity but the content of vitamin A here is in beta carotene form which possesses no harm to the body even if it is consumes in a large amount. This is due to that it cannot be converted efficiently enough in the body to cause toxicity. Instead, the excess will stored under the skin in the fat tissues which will turns the skin color into yellowish.

Combination of both persimmons and sweet potato will only cause gastric hemorrhage, gastric ulcer or bezoar. It is not truth in the myth that consumption of persimmons and sweet potato together can cause vitamin A toxicity. Instead, it is a good component for antioxidant compound due to the beta carotene and vitamin C in it.