Avocados

Like other fruits in the berry family, nutritional research involving the avocado’s ability to prevent or fight disease is relatively new, and very unfinished. However, because of their unusual and unexpected nutritional properties, researchers are intrigued.

Cancer

In vitro studies have determined that avocado causes apoptosis of cancer cells. This is not unexpected, since avocados have potent anti-inflammatory and

antioxidant properties. The unusual part is that avocado treats cancerous cells in just the opposite way that it treats healthy cells. In cancer cells, avocado encourages over-oxidation, causing apoptosis. In healthy cells, avocado reduces oxidation and inflammation, thereby protecting the cell’s health and integrity. It’s as if avocado can tell the difference between healthy and malignant cells, and treats them accordingly. This is especially interesting when we consider advanced tumors. Researchers are discovering that oxidation plays a different role in advanced tumors than it does in cancers that are still in the early stages. Research is currently under way to determine how avocado treatment results differ in early versus late-stage cancers. (1,2,4,5)

Cardiovascular and Heart Benefits

While not intended to be a definitive study, research published in the Journal of the American Heart Association, consuming one avocado a day may help reduce low density lipoprotein (LDL) cholesterol levels among overweight and obese individuals.

Penny M. Kris-Etherton, PhD, a professor of nutrition at Pennsylvania State University, and her associates recruited 45 overweight or obese participants between the ages of 21 and 70 years. The participants followed one of three cholesterol-lowering diets for five weeks:

a lower-fat diet without avocado
a moderate-fat diet without avocado
a moderate-fat diet with one Hass avocado a day

Moderate-fat diet participants gained 34 percent of calories from fat, 17 percent of which were from monounsaturated fatty acids (MUFAs). Participants in the lower-fat diet received 25 percent of calories from fat, 11 percent of which were from MUFAs.

The participants eating the moderate-fat diet with one avocado per day lowered LDL levels an average of 13.5 milligrams per deciliter, versus 8.3 milligrams per deciliter for the low-fat diet and 7.4 milligrams per deciliter for the moderate-fat diet with no avocado.

Researchers also tested a number of additional blood measurements including total cholesterol, small dense LDL, triglycerides, and non-HDL (high-density lipoprotein). The moderate-fat diet with one avocado a day resulted in improvement in all three areas compared with the other two diets.

Kris-Etherton warned us that the study was limited; “This was a controlled feeding study, but that is not the real-world — so it is a proof-of-concept investigation. We need to focus on getting people to eat a heart-healthy diet that includes avocados and other nutrient-rich food sources of better fats.” (6)

Arthritis

Scientists have been aware of the fatty properties of avocado for many years, but recent research has discovered that avocados contain a special kind of fatty alcohols, polyhydroxylated fatty alcohols, that are usually only present in aquatic plants, especially plants that grow in the ocean. These fats provide potent anti-inflammatory properties. In addition, avocados contain fats called phytosterols, which are known to reduce inflammation, especially inflammation that results from arthritis. (7, 8)

Research scientists agree that the wide array of phytosterols and carotenoids working with the unusual fat content of acvocados result in undoubted anti-inflammatory properties. The combination of these nutrients seems to work together to control inflammation caused by both osteo and rheumatoid arthritis.

In fact, avocados are known to prevent arthritis as well. Researchers believe avocado’s phytosterols play a major role in the prevention of arthritis by limiting the amount of prostaglandin E2 synthesis in connective tissue. Prostaglandin promotes inflammation.

Diabetes

Avocados are unusual in another way. They contain rare forms of carbohydrates called 7-carbon sugars. While avocados are a very low glycemic food, with only about 2 grams of total sugar, 7-carbon sugars make up about 60 percent of that total until they are picked. After they are picked, the 7-carbon sugars slowly change form, until after about five days they only make up about 40 percent of the total sugar content. Scientists are excited about the 7-carbon sugars because they hope to discover that the 7-carbon sugars will prove to help stabilize blood sugar levels by blocking activity of the hexokinase enzyme, which would alter the level of activity through a metabolic pathway called glycolysis. (11)

Additional Health Benefits

There is no better way to demonstrate how different foods work together, creating a synergy that protects us from and even cures disease, than to explain how the oleic acid in avocados helps us absorb fat soluble carotenoids such as lycopene and beta-carotene. Lycopene, especially, has been proven to provide many health benefits, but it isn’t easy for our bodies to absorb because it isn’t soluble in water. According to research done by the Department of Food Science and Technology, The Ohio State University, Columbus, OH, and published in PubMed, when oleic acid from avocados and the fat soluble carotenoids mix in our stomachs, they form a molecule that is easily absorbed by our bodies. Researchers state that when we mix avocado or avocado oil with salad or salsa, we absorb 200 to 400 percent more carotenoids. (12)

That’s a very good reason to eat avocados, especially with greens and tomatoes, which both contain large amounts of the carotenoids.

The neat thing is, so do avocados. They not only provide the oil to help us digest the carotenoids, they provide the carotenoid.

References

(1) Ding H, Chin YW, Kinghorn AD, et al. Chemopreventive characteristics of avocado fruit. Semin Cancer Biol. 2007 Oct;17(5):386-94. Epub 2007 May 17.

(2) Lu QY, Arteaga JR, Zhang Q, Huerta S, Go VL, Heber D.Inhibition of prostate cancer cell growth by an avocado extract: role of lipid-soluble bioactive substances. J Nutr Biochem. 2005 Jan;16(1):23-30.

(3) Unlu NZ1, Bohn T, Clinton SK, Schwartz SJ. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. J Nutr. 2005 Mar;135(3):431-6.

(4) Ding H, Chin YW, Kinghorn AD, D’Ambrosio SM. Chemopreventive characteristics of avocado fruit. Semin Cancer Biol. 2007 Oct;17(5):386-94. Epub 2007 May 17.

(5) D’Ambrosio SM, Han C, Pan L, Kinghorn AD, Ding H. Aliphatic acetogenin constituents of avocado fruits inhibit human oral cancer cell proliferation by targeting the EGFR/RAS/RAF/MEK/ERK1/2 pathway. Biochem Biophys Res Commun. 2011 Jun 10;409(3):465-9. doi: 10.1016/j.bbrc.2011.05.027. Epub 2011 May 8.

(6) Li Wang, PhD; Peter L. Bordi, PhD; Jennifer A. Fleming, MS, RD; Alison M. Hill, PhD; Penny M. Kris-Etherton, PhD, RD Effect of a Moderate Fat Diet With and Without Avocados on Lipoprotein Particle Number, Size and Subclasses in Overweight and Obese Adults: A Randomized, Controlled Trial Journal of the American Heart Association, May 2015.

(7) Zborovskii AB, Akhverdian IuR, Sivordova LE, Simakova ES, Zavodovskii BV. Efficiency of unsaponifiable compounds of soya beans and avocado in health care personnel with osteoarthrosis in Volgograd. Med Tr Prom Ekol. 2013;(2):41-4. Russian. PMID: 23

(8) Christensen R1, Bartels EM, Astrup A, Bliddal H.Symptomatic efficacy of avocado-soybean unsaponifiables (ASU) in osteoarthritis (OA) patients: a meta-analysis of randomized controlled trials. Osteoarthritis Cartilage. 2008 Apr;16(4):399-408. Epub 2007 Nov 26.

(9) López Ledesma R1, Frati Munari AC, Hernández Domínguez BC, Cervantes Montalvo S, Hernández Luna MH, Juárez C, Morán Lira S. Monounsaturated fatty acid (avocado) rich diet for mild hypercholesterolemia. Arch Med Res. 1996 Winter;27(4):519-23.

(10) Carvajal-Zarrabal O, Nolasco-Hipolito C, Aguilar-Uscanga MG, Melo Santiesteban G, Hayward-Jones PM, Barradas-Dermitz DM. Effect of dietary intake of avocado oil and olive oil on biochemical markers of liver function in sucrose-fed rats. Biomed Res Int. 2014;2014:595479. doi: 10.1155/2014/595479. Epub 2014 Apr 17.

(11) Xuan Liu, James Sievert, Mary Lu Arpaia, Monica A. Madore Posulated Physiological Roles of the Seven-carbon Sugars, Mannoheptulose, and Perseitol in Avocado Department of Botany and Plant Sciences, University of California, Riverside, CA 92521. J. Amer. Soc Hort. Sci. 127(1):108-114, 2002

(12) Mark L. Dreher and Adrienne J. Davenport Hass Avocado Composition and Potential Health Effects. Crit Rev Food Sci Nutr. 2013 May; 53(7): 738–750. Published online 2013 May 2. doi: 10.1080/10408398.2011.556759 PMCID: PMC3664913