Avocado Oil

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Avocado oil is an edible oil of exceptional aroma, powerful antioxidant power and renowned for its flavor. It is often compared to olive oil, mainly because it too contains high levels of a fat known as oleic acid. But there are so many differences between avocado oil and olive oil and there is frankly no substitute to the exotic touch of avocado oil. As we shall see, recent research has brought out credible evidence about the powerful antioxidant effect that avocado oil exerts on the cells of kidney and even the brain. It contains healthy fatty acids, vitamin E, chlorophyll and squalene that promote a naturally smooth, healthy skin. This oil holds promise in treating diabetes too.



Source

Avocado is fleshy, fatty and aromatic fruit (when ripe) which is actually a large berry. Its latin name is Persea americana. They had been eaten for centuries in central and southern American civilizations like those of the Aztecs and the Incas. It was discovered by colonial settlers and from there on, it was spread to Europe, northern America and even in some parts of Asia. Avocadoes grow in large numbers on a tree that is not very tall, kind of like a lemon tree. The fruit being heavy hangs low, dragging the branches down with it. Ripe avocadoes have a shiny greenish peel, which often turns into an almost blackish green. Inside lies the flesh and a large, hard seed.

Avocado oil is expelled not from the seeds, as one might think. It comes from the flesh of avocadoes. In this respect, avocadoes are quite unique because they are among a select few fruits that have fatty flesh. Because it is extracted from flesh, it contains a high concentration of polyphenols, chlorophyll and other micronutrients that lend it remarkable medicinal properties.

Color and Aroma

Cold pressed oil from organically grown or wild fruit has a matte yellow color with strong tint of dull green. Just when it is coming out of the expeller it looks emerald green. There are minor differences in color of oil depending on the variety (cultivar) used. Most commonly grown avocado is the Hass variety. Refining of oil reduces the greenish shade by wiping off chlorophylls. It then acquires an overall bright yellow color due to the carotenoids.



When cold pressed, it possesses a strong aroma which is strongly reminiscent of the fruit. It is described as buttery, grassy with some hints of nutty aromas. Overall the smell is quite pleasant. Refining reduces much of the aroma which makes it bland to taste and subsides it alluring aroma.

Properties

Avocado oil’s therapeutic properties make it quite suitable for people with dry, undernourished and even damaged skin. These benefits derive legitimacy from its chemical composition and peer reviewed medical studies.

  • Skin regenerative– It boosts collagen production. Collagen is one of the proteins that our body manufactures to forms a structural matrix of fibers making up the inner layer of our skin, the dermis. As we age, collagen and elastin based structural matrix degrades, leaving our skin old and sagging. [1]
  • Anti-inflammatory – Inflammation is often a parallel side effect caused by our immune response to an external stimuli. Our skin bears the onslaught of inflammation in the form of dermatitis, redness, swelling and/or pain. Avocado oil exerts a modulating effect on our immune response. Secondly, its healing and regenerative effects on the surface help to soothe an existing inflammatory reaction. [2]
  • Wound healing – Anti-inflammatory action of avocado oil is appreciable in case of healing up minor injuries. [2]
  • Antioxidant – Avocado oil seems to be possessing powerful free radical absorption capacity, a measure of antioxidant power. Intake of foods that are also potent antioxidants provides health benefits on a cellular level. Avocado oil increases levels of glutathione which plays a role in protecting our cells from free radicals. [3] It not only protects but also alleviates the damage to kidneys perpetrated by diabetes.
  • Metabolic maintenance – Virgin avocado oil was found to prevent metabolic disruptions in mice who were fed a high cholesterol diet. [4]
  • Hypertension alleviator – In a prominent study, avocado oil performed similar to angiotension II blocker medicine in alleviating the damaging effects of chronic high blood pressure on the functioning of the kidneys. It is known that the kidneys and eyes are most susceptible to damage due to elevated blood pressure levels. Avocado oil could form a nutritional approach to counter hypertension especially given the fact that its performance is comparable to most commonly prescribed medication. [5]

Health Benefits and Uses

Avocado oil for Skincare

Avocado oil aids in regeneration of skin from the bottom up. While many commonly used oils help only to moisturize and soften the skin, few have the capacity to rebuild the structure of skin. Regular application of cold pressed organic avocado oil can keep the dermis layer in pristine condition, preventing premature sagging. It can also prevent stretch marks because they are also formed as a result of tears within the dermis, for example when we gain and lose weight rapidly. When used over a considerable period, it can also lead to noticeable reduction in ageing visible on the skin.

Contrary to popularly held belief, avocado oil does not penetrate into the skin fast. It should therefore be applied liberally and should not be washed off very quickly. Let the skin soak it up. Besides its regenerative properties, it also exerts an emollient effect. This means that application of avocado oil prevents internal moisture from evaporating out, keeping our skin moisturized. Well hydrated skin looks healthier and feels smooth.

Even medical studies note that it is quite useful in alleviating the problem of chapped skin. It heals skin that has been damaged and appears cracked because of dryness and is often used to dissolve out flakes that form on drier regions of our face, elbows and heels. [2]

Avocado oil and Acne

It is generally not advised for application on acne because it has a considerable potential of clogging pores due to its comedogenicity rating of 3. It does not contain high levels of omega-3 fatty acids that are known to calm inflammatory reactions that aggravate acne. Since avocado oil may clog pores when applied topically, there is another way to go. Avocado oil can be used as a drizzle on salads, just like olive oil. This way we can obtain the nutrients of avocado oil and see if it aids in stopping the breakouts.

Some people have mentioned that avocado oil works fast at reducing sebaceous filaments on and near the nose in those with dry skin that is not prone to acne. Avocado oil would form a perfect skincare oil for people with chronic dry skin.



Avocado oil for Haircare

It can help our hair in two ways. Its fatty acids provide moisturization to hair strands, preventing them from drying out. Our hair is structurally made up of dead cells, but it does contain water and fats. Effective moisturization prevents frizz to some extent and also makes long hair more manageable while combing.

Secondly, vitamin E in avocado oil protects hair strands from sun damage caused by intense ultraviolet radiation as well as from heat. However, extra virgin and virgin avocado oil has a thick consistency which may be difficult to wash off. Moreover its aroma is more suited to food stuff than to hair.

It seems better to use it as a pre-shower conditioner. A small amount of avocado oil can be smeared on the palms and gently massaged into the hair strands. Then it should be washed off with running cold water because that is a quick way to keep hair from turning out greasy.

Diabetes

Medical research points to profound beneficial effects of avocado oil for those suffering from diabetes, specifically type-2 diabetes. In a long-term medical study avocado oil consumption reduced blood glucose levels, reduced the generation of free radicals (formed by lipid peroxidation mechanism), improved levels of glutathione (a powerful antioxidant). Mitochondria are sub-systems of all our cells that are primarily doing the work of generating energy for our daily tasks. Free radicals constantly bombard mitochondria and weaken them. Without healthy mitochondria providing energy for the needs of each cell, the cells themselves begin to decay and slowly die out. This gradual degradation puts an entire organ at risk, and eventually our entire body. Avocado oil protected mitochondria of the cells of kidney (known as nephrons). [3]

In simpler terms, regular consumption of virgin avocado oil alleviates diabetic nephropathy. But before deciding to include it in diet as an alternative or complementary medicine, it is vital to consult the doctor regarding suitable dosage and drug interactions that may arise.

Another study confirmed similar action of avocado oil on mitochondria of brain cells. Here too, avocado oil protected the brain cell from free radicals that were on an increase due to diabetes. This study has implications for treatment of diabetic encephalopathy, in which high blood glucose levels and other  associated effects of diabetes progressively damage the nerves. [6]

We most definitely need in-vivo studies conducted on human population affected by diabetes to know more about such alleviating effects of avocado oil on this condition.

High Blood Pressure

Hypertension leads to higher than normal blood pressures, diastolic, systolic or both. When blood pressures remain elevated for prolonged periods, it is detrimental to health. Most sensitive to blood pressure changes are the kidneys and eyes. In a study, rats fed avocado oil showed considerable reduction in systolic (15.5%) and diastolic (21.2%) pressures. This was comparable to the reductions in blood pressure due to angiotensin blockers, a category of medicine very commonly used for this condition. This is of immense significance not just for those whose blood pressures lie close to the threshold on average, but more so for the aged who have to deal with high blood pressures as a natural consequence of ageing. With age, our arteries begin to lose their natural elasticity and they are more susceptible to damage by higher blood pressures.

The study also corroborated the effects seen in studies conducted on the effects of avocado oil in diabetes, which we have mentioned in the section just above. Avocado oil has a protective effect on the kidneys and boosts the levels of natural antioxidant, glutathione in our blood. [7]

High Cholesterol

Regular consumption of avocado oil may or may not increase total blood cholesterol (whether in LDL, VLDL or the healthier HDL form). But one study found out that when rats are kept on a high cholesterol diet, avocado oil helps to minimize the deleterious effects. It restores the processes that govern how our body absorbs and assimilates fats and amino acids. It also helps to restore gut flora back to normal levels. [4] Avocado oil could therefore be useful for men and women who must be on a temporarily high fat diet, for example, bodybuilders often go through a phase of bulking up before they work at building a leaner yet appreciably muscular physique.

As a Cooking Oil

Avocado oil is generally used only as a salad dressing. But did you know that it is one of the best oils for deep frying because of its unique thermal stability? When we deep fry food stuffs, the oil undergoes hydrogenation and the amount of saturated fats, trans fats and polar compounds increases. Deep fried foods should therefore be made in oils that have high smoke points. Avocado oil has a smoke point of about 250 °C, which is the highest among all commonly used edible oils. Refined avocado oil has an even higher smoke point. But refined oils do not impart much flavor as they are bland. They are deodorized and preservatives are added to increase their shelf life. Unrefined avocado oil, with its deep color and noticeably buttery flavor really makes the same dishes taste a little different than what a refined sunflower or refined soybean oil would create.

Secondly, unrefined avocado oil has much more amounts and variety of vitamins and especially, micro-nutrients.

Thirdly, avocado oil’s fats improve the absorption of carotenoids from salads. Sprinkling avocado oil on chopped carrots, tomatoes, cabbage, lettuce etc would allow our body to get more carotenoids. [8] These micro-nutrients have tremendous health benefits as antioxidants for the skin and eyes and some of them also act similar to vitamin A.

Nutritional and Medicinal Information

Relative proportion of fatty acids in avocado oil suggests that it is similar to olive oil. Both are rich in oleic acid, a mono-unsaturated fat. Complete breakdown of fatty acids in a representative sample of avocado oil is obtained from USDA.

Fatty acid Carbon notation Percentage
Palmitic acid C 16: 0 (Saturated) 10.9%
Stearic acid C 18: 0 (Saturated) 0.66%
Palmitoleic acid C 16: 1 (MUFA) 2.67%
Oleic acid C 18: 1 (MUFA) 67.89%
Linoleic acid C 18: 2 (PUFA) 12.53%
Alpha-linolenic acid C 18 : 3 (PUFA) 0.96%

Source: 9

Oils that are rich in oleic acid have emollient effect on the skin. They moisturize the skin and keep it hydrated. Massage using such oils has a pain-relieving effect. It increases the speed of wound healing. Internally, it is known to reduce blood pressure and have a modulatory effect on the immune response. However, it is not much of an antioxidant, and on the contrary is very susceptible to rancidity.

What differentiates cold pressed avocado oil from similarly extracted olive oil are certain micro-nutrients that are not found in similar compositions in olive oil.

Avocado oil contains an impressive array of carotenoids like alpha-carotene, beta-carotene, cryptoxanthin, lutein and zeaxanthin. [10] Since these nutrients are fat soluble, they inevitably end up into the oil upon mechanical pressing. Except lutein and zeaxanthin, all others can be converted by our digestive enzymes into vitamin A. Consumption of avocado oil can therefore provide adequate vitamin A. Lutein and zeaxanthin are particularly useful in protecting our eyes from the harmful effects of blue wavelengths of light. They also slow age-related macular degeneration and reduce the risk of glaucoma in old age.

Avocado oil contains plant derived sterols, known as phytosterols. These are micro-nutrients that block absorption of cholesterol in our intestines and are responsible for cardioprotective effect of many vegetables and some oils. Phytosterol profile is mentioned in table below.

Phyto-sterol Amount in mg per kg
β-sitosterol 80 mg/kg
∆5-avenasterol 4.3 – 9.26 mg/kg
campesterol 3.71 – 6.09 mg/kg

Source: 11

Avocado oil also provides a powerful micro-nutrient called squalene. It is generally found in useful amounts in oils of grains and in olive oil. Avocado oil can contain anywhere from 200 mg per kg from avocadoes grown in colder marine climates like in New Zealand and Chile, to a whopping 1350 mg per kg from avocadoes grown in tropical evergreen climates in Mexico and Central America. [11] Squalene has very potent anti-ageing and anti-inflammatory effects and is ubiquitously used to maintain a youthful glow on the skin. It resembles our body’s natural oil the most. Squalene is also used as a standalone supplement in acne, psoriasis, seborrheic dermatitis and atopic dermatitis. Besides its antioxidant effects wherein it arrests lipid peroxidation, it has been found to modulate immune function, reduce cholesterol and triglycerides and some recent studies even point to its usefulness as an adjunct therapy for certain cancers. [12]

Virgin and extra virgin avocado oil contain appreciable amount of chlorophyll and its derivatives (like phaeophytins). Chlorophyll as we know from basic science is the group of molecules that are at the very heart of sustenance of plant life on earth. We all derive our existence from plants. In humans, chlorophyll is not vital for existence, but it exerts powerful anti-inflammatory and antioxidant effects. Avocado oil contains around 20 to 70 mg per kilogram of chlorophyll derivatives which is comparable to that found in extra virgin olive oil. [13] It is easy to spot avocado oil rich in chlorophyll. It has a much greener tint to its color, almost like emerald green. However, chlorophyll decays fast and the oil begins to turn matte yellow. Refining processes remove chlorophyll because otherwise it is prone to rancidity. It would be prudent to buy extra virgin avocado oil in small quantities so that you do not have to keep it in storage for long.

Avocado oil provides vitamin E mainly in the form of alpha-tocopherol and gamma-tocopherol, but some cultivars also contain delta-tocopherol. Vitamin E too acts as a potent antioxidant for the entire body. Topical application of oils rich in alpha tocopherol prevents our skin from UV damage. Its most definitive role is in protecting our nerves from neuro-degenerative diseases.

Side Effects, Safe Dosage and Toxicity Issues

Avocado oil that is extracted from organic sources through mechanical processes (like cold pressing) without the use of solvents (like hexane) is quite safe to apply on the skin, and also to consume internally. It poses negligible risk of contact allergy or sensitization. It may cause some allergic reaction if it contains some amount of seed oil, that is, if avocado seed was also pressed into the oil. Therefore, it is essential to purchase the oil from a reputed manufacturer of edible oils.

Since we have understood that avocado oil can be used as a medicinal oil to lower blood pressure and to relieve symptoms of diabetes, we need to exercise caution when taking it internally. Appropriate dosage for a specific condition can be judiciously decided by a doctor. We currently do not know about toxic effects of avocado oil, if any.

Buying and Storage

Compared to olive oil, there are nowhere as many brands making and selling cold pressed avocado oil. Although avocadoes are native to Central America, most of the highest grade edible avocado oil actually comes from New Zealand, which is quite surprising. It is quite possible that oil from New Zealand may be having different composition of micro-nutrients than those coming from the equatorial regions. Chile, like New Zealand too has jumped the bandwagon and started cultivating avocadoes.

Cold pressed and unrefined Avocado oil does not have a good shelf life because of the abundance of unsaturated fats and chlorophyll. It must be kept in a thick glass or stainless steel container with air tight lid. To reduce oxidation that causes rancidity, it should be kept in cool but dry place where moisture does not accumulate.

References

  1. The effect of various avocado oils on skin collagen metabolism. Werman M.J. et al, Connect Tissue Res. 1991;26(1-2):1-10.
  2. Anti-Inflammatory and Skin Barrier Repair Effects of Topical Application of Some Plant Oils. Tzu-Kai-Lin et al, Int J Mol Sci. 2018 Jan; 19(1): 70.
  3. Avocado oil induces long-term alleviation of oxidative damage in kidney mitochondria from type 2 diabetic rats by improving glutathione status. Ortiz-Avila O. et al, J Bioenerg Biomembr. 2017 Apr;49(2):205-214.
  4. Effect of virgin avocado oil on diet-induced hypercholesterolemia in rats via 1 H NMR-based metabolomics approach. Tan CX et al, Phytother Res. 2018 Nov;32(11):2264-2274.
  5. Comparative effects of avocado oil and losartan on blood pressure, renal vascular function, and mitochondrial oxidative stress in hypertensive rats. Márquez-Ramírez CA et al, Nutrition. 2018 Oct;54:60-67.
  6. Avocado Oil Improves Mitochondrial Function and Decreases Oxidative Stress in Brain of Diabetic Rats. Amar Ortiz-Avila et al, J Diabetes Res. 2015; 2015: 485759.
  7. Comparative effects of avocado oil and losartan on blood pressure, renal vascular function, and mitochondrial oxidative stress in hypertensive rats. Marquez Ramirez et al, Nutrition. 2018 Oct;54:60-67.
  8. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. Unlu N.Z. et al, J Nutr. 2005 Mar;135(3):431-6.
  9. Full Report (All Nutrients): 04581, Oil, avocado
  10. Avocados – whfoods.com
  11. Chemical characterization of commercial and single-variety avocado oils. G.D. Fernandes et al, Grasas y Aceites, Instituto de la Grasa.
  12. Amaranth Seed Oil – OilHealthBenefits.com
  13. A Review of Extraction Techniques for Avocado Oil. Xiaoli Qin, Jinfeng Zhong, Journal of Oleo Science.

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