It never occurred to me that one should not eat Chaya leaves frequently but I recently met someone who was well-informed and said it should be limited to once a week or once each two weeks. That conversation was within the context of the normal guidelines of boiling it for awhile before eating it.
Is there any reliable data suggesting it should be eaten rather infrequently?
Hi Glen,
Interesting, I have not heard of a limitation on the frequency of eating properly cooked chaya before. @Nadezda_Amaya is this something that you would be willing to speak into, given your knowledge of how chaya is consumed?
Today I went back for another conversation on this topic and he said the problem is oxalate…oxcalic acid. That chaya is an extra high source of oxcalic acid and those who are sensitive could have problems because chaya is extra high source of oxalate, and those who are sensitive could have problems by consuming it regularly.
In other words, the problem with high usage is not the problem of hydrocyanic glycosides which is easily avoided by boiling.
That makes more sense!
I am not a nutritionist so I don’t fully understand the complexities of the various oxalates and human health. I did find one article by Babalola and Alabi (2015) that looked at the effect of different cooking methods on the oxalate content of chaya, but I don’t know if the reduction of oxalates is enough for safe, daily consumption. I also don’t know if they looked into the solubility aspect of oxalates. I’ve asked a nutritionist who is a good friend of ECHO to look into this and hopefully will get back to you soon!
Reference:
Babalola, J.O. and O.O. Alabi. 2015. Effect of processing methods on nutritional composition, phtochemicals, and anti-nutrient properties of chaya leaf (Cnidoscolus aconitifolius). African Journal of Food Science 9(12): 560-565.
Below is a summary from Dr. Witt, a nutritionist who helps ECHO staff answer some questions on human nutrition:
Oxalates are poorly digested natural compounds found in many plants. Their metabolism is complex. Oxalates in foods can bind with minerals like calcium and iron, reducing the absorption of both oxalate and the minerals. This property of oxalates is what the designation “anti-nutrient” is based on. Boiling foods causes some of the oxalates to leach out into the cooking water, reducing the oxalate content of the food (Chai and Liebman, 2005). Once consumed, oxalates can also be broken down by a bacteria in the large intestine, reducing the amount of oxalate which is absorbed. The oxalate which is absorbed mixes with the oxalate produced by our bodies. Excess oxalate is typically filtered out of the blood by the kidneys and is excreted in the urine.
The oxalate content of chaya is high, but not above that of many commonly consumed foods. Fresh chaya leaves contain about 63 - 78 grams/100 grams and boiling for 15 - 20 minutes reduces the oxalate content to 30 - 53 mg/100 grams (Balola and Albi, 2015; Adamu et al., 2020). For comparison, some foods that are very high in oxalates are spinach leaves (600 - 970 mg/100 g), rhubarb (460 - 620 mg/100g) and almonds (300 - 400 mg/100g ). Some other foods which are considered high in oxalate are navy, black or kidney beans (about 30 mg/100g), okra (10 - 50 mg mg/100 g), and cashews (150 mg/100 g).
Most people eating a varied diet providing an adequate level of minerals and moderate amounts of high oxalate foods do not need to be concerned about their oxalate intake, but individuals with a few medical conditions may be advised by their health care provider to limit their oxalate intake. Some people have a type of kidney stone which is related to high levels of oxalate in the urine. Other reasons for limiting oxalate intake include a rare genetic condition causing the body to make excess oxalates, kidney disease, and significant malfunction or removal of the intestines. It is also important to note that while typical human dietary patterns provide safe levels of oxalate intake, there are a few case reports of individuals who developed kidney damage from excessive oxalate intake. These cases have typically resulted from unusual dietary habits including regular, excessive intake of foods that are high in oxalates.
With the exception of breast milk for infants, I would not recommend that anyone eat a large portion of the same food every day, as dietary variety helps to provide us with all of the nutrients we need and helps us to avoid excessive intake. (see Dr. Price’s EDN article on eating a diversity of food options.)
References
Adamu, H. M., Bara, P. G., & Ushie, O. A. (2020). The Proximate Composition and Anti-nutritive Content of Cnidoscolus aconitifolius Leaves. International Journal of Biochemistry Research & Review, 29(8), 65–73. The Proximate Composition and Anti-nutritive Content of Cnidoscolus aconitifolius Leaves
Babalola, J.O. and O.O. Alabi. 2015. Effect of processing methods on nutritional composition, phytochemicals, and anti-nutrient properties of chaya leaf (Cnidoscolus aconitifolius). African Journal of Food Science 9(12): 560-565.
Chai W, and M. Liebman. 2005. Effect of different cooking methods on vegetable oxalate content. J Agric Food Chem. Apr 20;53(8):3027-30. doi: 10.1021/jf048128d. PMID: 15826055.
Values for the oxalate content of foods from oxalate.org.