Cashews (cashew nuts, kernels)

Cashews sold at the grocery store are seldom raw. Read more to find out why. The nut shell liquid in cashews is toxic and can only be removed by applying high heat. The term “raw” therefore misleads consumers. This video about the production of cashews shows the complex manufacturing process that is carried out almost completely by hand.¹

Culinary uses:

Cashews have a sweet, nutty flavor and are available commercially “raw,” roasted, or roasted and salted. In this case, “raw” simply means not roasted. Cashews are a common snack food. They are also used in muesli or toasted in a skillet and then added to salads or other dishes. Finely ground, they are used to make vegan cheese and many other products. Although they are unhealthy, cashews are particularly popular in the vegan scene and among raw foodists (who haven’t informed themselves). See the link below.

Nutritional information:

Cashews contain high amounts of the essential amino acid tryptophan, which is important for the production of the neurotransmitter serotonin. Together with vitamin B₆ (e.g., in brewer’s yeast and potatoes), consuming tryptophan can alleviate depression in cases where the depression is caused by a lack of this amino acid. And cashews also naturally contain a wide range of minerals such as magnesium and iron. Cashews have a buttery, slightly sweet flavor that can cause us to eat too many.

Unfortunately, cashews contain high levels of omega-6 fatty acids (linoleic acid, LA, 7.8 g/100 g) and very low levels of omega-3 fatty acids (alpha-linolenic acid, ALA) — even those that are sold as “raw.” The ratio of LA to ALA is at least 48:1 and can be up to 130:1. People who eat a Western diet usually consume a ratio of about 10:1 instead of the desired 2:1; health authorities are therefore trying to bring this ratio down to at least 5:1. And vegans and vegetarians can show a ratio of 17:1 to 24:1 — to a large extent because they eat more cashews — a nut that promotes all kinds of inflammatory processes in the long term. The receptors for linoleic acid alpha-linolenic acid are the same, although the first promotes inflammation and the latter helps reduce it.

At 160:1, peanuts have an even worse LA:ALA ratio, but they still play an important role in most vegan and vegetarian diets.

Health aspects — effects:

All we can do is to warn people: Incorrectly or uninformed vegans and vegetarians generally have a poorer diet than “normal eaters” — there will surely soon be a study that will show the incontrovertible evidence (for more info, see link in the box above). This would then stop the vegan hype — which is so important for animal welfare and the environment — and discredit this lifestyle. This has been our fear since 2014! Read here about something similar that happened with the raw food movement (The Giessen Raw Food Study).

Recommendations made by Switzerland’s Federal Commission for Nutrition (FCN) in 2006:

At the request of Switzerland’s Federal Office of Public Health (FOPH), the FCN was commissioned in 2003 to adapt the recommendations from 1992 regarding fats and oils to be in line with the latest scientific findings. Under the ingredient olive oil, we have described these in detail. Here we will just provide an overview of the key points.

Polyunsaturated fatty acids are essential and are divided into two main groups (there are also others): linoleic acid and its derivatives as a group of the n-6 or omega-6 fatty acids (LA) and α-linolenic acid or alpha-linolenic acid — which is often just called linolenic acid or ALA (omega-3 or n-3) — and its derivatives. Vegetable oils² are the main source of inflammatory LA, but nuts and seeds also contain significant amounts! The main sources of healthy anti-inflammatory omega-3 (ALA) include canola oil, flaxseeds, walnuts, and leafy vegetables.²

Health-conscious people get omega-3 from flaxseed, chia seeds, walnuts, macadamia nuts, hemp seeds, herbs, and leafy vegetables because these have a particularly good LA:ALA ratio. On our site, you can click on an ingredient in the ingredient list for any recipe and then scroll down to the end of the text. There you will find detailed nutrient tables for the ingredient (with only a few exceptions). The recipes also include detailed nutritional information in table form. For example, Erb Muesli has an ideal combination of ingredients that yield a LA to ALA of 1:1.

Direct statement from the FCN: Excessive consumption of n-6 fatty acids can promote thrombosis and inflammation. It is therefore a good idea to focus on reducing the ratio from n-6:n-3 to a maximum of 5:1. Today, most people consume these fatty acids in a ratio of approx. 10:1. There is evidence that lowering this ratio can reduce the risk of atherosclerosis and prevent or slow inflammatory processes.²

Dangers/Intolerances:

If you ever have access to a cashew tree, you must resist the temptation of picking and eating the cashews straight from the tree (Anacardium occidentale)! Their shells contain a toxic nut shell liquid that has to be deactivated by roasting or steaming. If the oil comes into contact with the mucous membranes, it can cause severe burns. The oil has serious irritating effects on the skin. The hard shells can only be opened by applying high heat.

Some people are allergic to cashews, but this allergy is much rarer than in the case of other species of nuts. All of the nuts in the Anacardiaceae family contain high amounts of essential oils and sometimes resins, acids, and phenols (cardol) ...³

We need to critically examine not only the consumption of cashews but also the manufacturing process as it takes place under precarious health conditions.

The production of cashews:

Cashew trees grow exclusively in tropical areas. The main growing areas for cashews are Vietnam, the Philippines, Indonesia, and many African countries. According to Wikipedia, the majority of exported cashews come from Africa: in 2016, it was 51.6 %. However, the nuts are processed primarily in Vietnam. This has a major impact on the environment, especially since it involves transporting raw cashews, which weigh five times as much as the shelled version.⁴

There are many small companies that harvest cashews and get them ready for trading (e.g., Peace Corps). This practice helps prevent an exodus from rural areas as it provides jobs for locals. However, consumers aren’t aware of the conditions under which production takes place. When buying cashews, please make sure to always buy organic and to look for labels such as FairTrade.

Cashews go through elaborate processing steps before they can be eaten. In addition to the time-consuming manual work, which requires a lot of tact and skill, the production processes can also be harmful to the workers’ health.

The entire cashew fruit (cashew apple and nut) is harvested. The cashew apple, a pear-shaped swollen stem on which the nut hangs, is very sensitive to pressure and cannot be stored. If it is to be further processed into cashew juice or jam, this must be done immediately after harvesting. And harvest residues such as sand and stones have to be removed. The cashews we know are actually the seed of the fruit that is contained in the hard shell that hangs under the cashew apple. The unpeeled seed accounts for about only 20 % of the total weight of the entire fruit. Before processing, the cashews have to be soaked in water for a few hours so that they don’t end up getting roasted when heated. The moisture content of the nut should be at least 9 %.⁵

The shell is very difficult to open without heating. There are a few traditional methods (e.g., in Sri Lanka), where they are opened individually by hammering them on stones. Direct contact of the toxic nut shell liquid with the mucous membranes can cause burns, which is why workers have to wear gloves. However, the rubber dissolves very easily upon contact with the corrosive oil. Workers often rub their hands with cooking oil, clay, wood ash, or potash to avoid direct contact with the skin.⁶

For larger quantities and especially for export, processes with high heat are used. Under high temperatures, the shell cracks relatively quickly and the cashews can be removed. To do this, the cashews are boiled, steamed, or roasted in large vats. However, this process is also associated with health risks. During the heating process (approx. 190 °C), the cardol found in cashews produces black smoke with corrosive vapors.

After a 24-hour drying phase in the shade, the outer shell can sometimes be opened by hand. In practice, a special device, resembling a nutcracker, is used that is operated with a foot pedal. To do this, the nut is placed between the sharp blades of the device and the shell is then split. There are also mechanical processes, but the risk of breakage is much greater. Here, too, there is still a risk of residual corrosive oil.

For protection, many workers use the natural means listed above instead of expensive gloves. Since the demand for white cashews is greatest, a further processing step is required to remove the thin, dark skin (also called testa) around the edible cashew kernel. To facilitate this process, the cashews are dried an additional time. Traditionally, they were placed in the sun or dried over an open fire at approx. 55–60 °C. However, today increasingly large quantities are dried using mechanical processes (e.g., in trays heated to approx. 70 °C). This process serves as protection against fungal attack and reduces the moisture to approx. 3 %. In this state, the cashews are particularly sensitive, which is why the shells are most often removed by hand. Mechanical processes result in about 30 % more breakage, which greatly reduces the quality.

In order to get a good price, the cashews have to be manually sorted after they are shelled. This is because machine sorting causes too much breakage — only large, whole cashews have the highest quality level. Before packing, the moisture content has to be brought back to about 5 % so that a greater stability can be guaranteed. At high humidity, this happens by itself and no further steps have to be taken. The cashews are packed in airtight containers, the oxygen is extracted, and they are also treated with CO₂ to prevent colonization by harmful fungi and bacteria.

General information:

Cashews (Anacardium occidentale) are native to South and Central America; often Brazil and Mexico are listed as the origin. They get their name from the Indian word for the cashew fruit “kaju,” but various tribes have also called them “merei” or “marañon.” The Indians also processed the cashews by roasting them, and they often used the oil in medical poultices. In addition, they pressed the cashew apples to make juices or wine.³ Botanically speaking, cashews are not nuts but instead seeds of an accessory fruit (sometimes called a pseudocarp or false fruit).

Cashew trees are now cultivated in all tropical countries, especially in Africa and in areas extending from India to Vietnam. Cashews didn’t become a major commodity until an industrial roasting process that removed the toxic oil was developed.⁷ The hard shell of the cashew actually consists of two shells, and in between is a chamber that contains the toxic cashew nut shell liquid (CNSL).

Today, CNSL is still usually removed via a roasting process. It contains anacaric acid (70 %), cardol (18 %), and cardanol (5 %), and is processed into synthetic resins, brake pads, clutch discs, paints, and other products.⁷ CNSL is also used for medical purposes.

From Wikipedia:
The cashew fruit contains the cashew apple and cashew seed. Cashew seeds are usually simply called cashews. Cashews are small, greenish to brownish, kidney-shaped or boxer- glove-shaped nuts that hang from a pear-like swollen stem. This 5–10 cm long, swollen stem that looks like a pear or sometimes a bell pepper and is known as the cashew apple. The cashew apple is an accessory fruit (since the cashew apple is only a swollen stem and not the actual, reproductive fruit of the cashew tree). When ripe, the cashew apple is yellow-orangish to red in color and is processed into kaschu juice and marmelade (jam).

Click on the following link to find out more about the ingredient dry-roasted cashews, unsalted.

Literature — sources:

1. Video: Cashew Nut Processing — Peace Corps
2. EEK_Bericht_Fette_in_der_Ernährung_2006_DE.pdf (Federal Commission for Nutrition (FCN) report on fat in our diet)
3. Brücher H. “Tropische Nutzpflanzen: Ursprung, Evolution und Domestikation” (Tropical crops: origin, evolution, and domestication). Berlin: Springer-Verlag. 1977
4. beobachter.ch Transport um die halbe Welt, der Irrsinn mit den Cashewnüssen (Transport halfway around the world, the madness surrounding cashews)
5. International Finance Corporation IFC. Prospects of Cambodia’s Cashew Sub-Sector. 2010
6. Azam Ali SH, Judge EC. Small-scale cashew nut processing. FAO. 2001
7. Rehm S, Espig G. “Die Kulturpflanzen der Tropen und Subtropen: Anbau, wirtschaftliche Bedeutung, Verwertung” (The cultivated plants of the tropics and subtropics: cultivation, economic importance, and recycling). Stuttgart: Eugen Ulmer Verlag. 1976

Author: Michael Weber | 23 Jan 2017