Health Benefits Of Pistachios

Introduction

Pistachios originated in Western Asia and the Middle East and have been consumed by many people over the last 8000 years. However, currently, they are mostly imported from countries such as Iran, the United States and Mediterranean countries. They grow best in dry climates and some pistachio trees can grow to 12 metres tall.¹

Even though pistachios are called nuts, they are seeds from the green grape-like pistachio fruit that grows on the tree Pistacia vera. Pistachios are drupes; however, unlike other drupes like peaches, cherries and apricots, the seed is eaten and the fruit discarded. These fruits normally grow in spring, but when it starts to ripen it gradually turn red and harden, resulting in the shell we associate pistachios with. When the ripening has finished, the shell of the pistachios opens, revealing the green pistachio inside.¹ Before being distributed worldwide, pistachios are dried either naturally in the sun or using a commercial drying tank. Following the drying, they are roasted and packaged into salted or unsalted bags.²

Pistachios contain a variety of different nutrients that contribute to several health benefits such as improving heart health, helping with weight loss and promoting a healthy gut. A serving of about 49 pistachio seeds (28 grammes) contains an average of 159 calories and the following nutritional values:

• 8 grammes of carbs
• 3 grammes of fibre
• 6 grammes of protein
• 13 grammes of fat¹

About pistachios 

Health benefits of pistachios 

Helps with weight loss 

Pistachios are naturally energy-dense due to their high content of both fibre and protein. This means that the body takes longer to digest pistachios compared to other foods resulting in eating less throughout the day.³  

There have been many studies on the weight loss properties of pistachios. Some studies have shown that the fat in pistachios is normally stuck in their cell wall resulting in malabsorption of fats. This means that the fats are not easily absorbed and digested by the gut. Other studies have taken a more psychological approach and concluded that the visual clue of seeing the pistachio shells, can result in a phenomenon described as mindful eating where people can recognise the amount of food they have consumed.⁴ 

Helping with diabetes

There have been several studies linking pistachios with preventing and helping people who suffer from type 2 diabetes. People with type 2 diabetes must keep their blood sugar levels regulated and stable. In general, pistachios have a low glycemic index, meaning that they keep blood sugar levels stable and do not cause a rapid increase in blood sugar levels. Pistachios can also help maintain stable blood sugar levels, when consumed alongside other foods, like carb-rich foods, that normally cause a dramatic spike in blood sugar levels.³

Improved eye health

Pistachios are rich in the antioxidants lutein and zeaxanthin which are beneficial to the eyes. These two antioxidants have also been linked to protecting the eyes from blue light and preventing age-related macular degeneration (AMD). AMD is a condition which appears with age and can cause vision blurriness and loss.⁴

Promotes healthy gut bacteria

The fibre in pistachios can be digested by good gut bacteria, boosting microbiome health. The bacteria can convert the fibre into short-chain fatty acids, like butyrate that contribute to other health benefits like reducing the risk of developing conditions like cancer, cardiovascular diseases and digestive disorders.⁴ 

Improves heart health

Pistachios have several components that have been proven to reduce heart disease. For example, pistachios contain antioxidants, polyphenols and tocopherols, that have properties that protect against heart disease. In addition, many studies have shown that pistachios can reduce LDL, also known as bad cholesterol and increase HDL, good cholesterol resulting in decreasing the risk of heart disease.

Another risk factor for heart disease is endothelium dysfunction. The endothelium is the inner lining of blood vessels and is important to regulate blood flow and pressure. Pistachios contain the amino acid L-arginine, which is converted by the body into nitric oxide to promote healthy blood vessels, hence reducing the risk for endothelium dysfunction and many heart diseases.⁴

Improves sleep

Compared to other nuts, pistachios contain a higher level of the hormone melatonin which is normally produced by the body that helps with regulating sleep patterns. Eating a few pistachios, 30 to 60 minutes before going to bed, may be the perfect bedtime snack.³

Prevents cancer

Antioxidants in pistachios contribute to many different health benefits, including the prevention of cancer. This is because antioxidants remove harmful free radicals, preventing cells from acquiring cancerous properties over time.⁴

In addition, the high fibre content in pistachios also plays a role in reducing some types of cancers. In general, diets that are rich in fibre have been linked to reducing the risk of getting colon cancer. One study of 800 colon cancer patients, proved that eating 2 or more servings of nuts weekly reduced the recurrence and death rate of getting cancer.³

Nutrients we can get from pistachios 

There are various nutrients in pistachios that contribute to several health benefits. Some of the nutrients with their corresponding recommended daily value in percentages (DV) are listed below:

• 6% Potassium
• 11% Phosphorus 
• 28% Vitamin B6 
• 21% Thiamine 
• 41% Copper
• 15% Manganese⁴

In addition to all of the nutrients in the pistachios, in 2019 an analysis conducted by the American Pistachio Growers concluded that roasted American pistachios are considered to be a complete protein. Complete protein refers to different sources of foods that have the 9 essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine) that the human body can't make. Usually, the majority of complete proteins come from animal-based food sources, making pistachios the best alternative for people who do not consume meat as part of their diet.³

Ways to include pistachios in our health

One of the biggest advantages of pistachios is their versatility meaning that they taste delicious in a range of different dishes. Pistachios are edible when raw however, due to transportation, they are normally roasted and can come either as salted or unsalted. These pistachios normally come in bags and can be eaten as easy snacks throughout the day. In general, roasted pistachios will normally last for an average of a year when stored in plastic bags. However, they can be frozen if needed but it is always recommended to defrost them before opening the packaging to prevent the building up of mould and fungus due to the dampness.²

Alternatively, pistachios can be incorporated into a variety of dishes. Whilst most people prefer to eat salted pistachios as snacks, unsalted pistachios are normally the preferred choice to incorporate into cooking. Some of the dishes in which pistachios can be incorporated are:

• Ice Creams
• Salads
• Grain Dishes
• Desserts and baked goods²

How much is enough?

It is important to consume pistachios in moderation and not eat too many of them daily. The amount of pistachios that should be consumed daily, recommended by nutritionists, is a maximum of 56 grammes or 90 shelled pistachios. This quantity should be enough to provide you with all the health benefits whilst ensuring that there are no severe side effects. In addition, it is always recommended to drink a lot of water when eating pistachios to aid with digestion, as a lack of water may lead to an upset stomach.⁵ One advantage of pistachios is that the shells can be used as visual clues to alert you if you are exaggerating and consuming too many pistachios.⁴

Side effects

Even though pistachios provide a variety of health benefits, they can cause some severe side effects if eaten in excess. This is because certain components of pistachios, like fructan and high fibre content, can lead to problems like digestive and gastrointestinal problems. 

Some of the most common side effects include:

Allergic reactions

Tree nut allergies, including pistachio allergies, are very common and can cause symptoms like nausea, diarrhoea, difficulty swallowing and anaphylaxis.

It is also important to note that people with pistachio allergies may experience cross-reactivity where they exhibit allergic reactions to other foods like certain fruits, soybeans and vegetables. This is because some components and substances share similar structures or are biologically related resulting in allergic reactions. It is especially good to be aware of cashews as they share many of the allergenic proteins as pistachios. If this happens, it may result in itchiness and swelling of the lips, mouth, tongue or throat. This phenomenon is due to a condition called pollen food allergy syndrome (PFAS) or also sometimes referred to as oral allergy syndrome (OAS). 

In addition, after identifying allergic reactions to pistachios, it is always best to avoid consuming them by taking preventative measures. These are some things which can be implemented into your daily lifestyle to avoid any allergic reactions:

• Reading the ingredients in some food products and paying close attention to the “may contain” section in food packaging
• Avoiding cross-contamination during cooking and eating
• Plan when travelling and let other companions know about your allergies
• Before ordering food at restaurants, it is always best to inform the staff about your allergies and ensure that there are no pistachios embedded in the dish
• Wearing a medical ID bracelet stating all your allergies and carrying any recommended medication at all times in case of emergencies

These are just some of the precautionary measures that can be taken to ensure that no allergic reaction is triggered. To understand more about allergies and your body's allergic reaction, it is always best to talk to a doctor who may prescribe you medication.⁵ 

High blood pressure

Raw pistachios are normally processed with a high amount of salt and sugar. Therefore, it is always best not to consume too many pre-packaged pistachios as it may increase the risk of hypertension and lead to some cardiovascular diseases.⁵

Kidney problems

In general, pistachios do not cause kidney problems. However, if you already have any pre-existing kidney problems, it may worsen the condition due to the high concentration of potassium. One of the main jobs of kidneys is to remove excess potassium in the body, therefore, the extra potassium from pistachios may not be fully removed if the kidneys are dysfunctional.⁵

Salmonella and aflatoxin infection

Salmonella and aflatoxin infections are two of the most common infections that can arise due to pistachios. Salmonella refers to a pathogenic species which normally occurs in dry fruit and normally affects pistachios when they come in contact with the ground. Salmonella infections normally lead to symptoms such as high temperature, diarrhoea and gastrointestinal problems. Similarly, pistachios are also susceptible to aflatoxin contamination especially when the shell has split, revealing the pistachio seed. Exposure to these contaminated pistachios leads to nausea, vomiting, and abdominal pain. 

To avoid Salmonella and Aflatoxin infections when consuming pistachios, it is recommended to roast the pistachios over dry heat. Some pistachios, like Iranian pistachios, can be heated at 180 degrees for 20 minutes. The heat that the pistachios will endure will result in the death of the pathogen and aflatoxins. Other pistachios, like American pistachios, have less tolerability to heat, but they are normally less likely to be contaminated by aflatoxins, so are generally safe.⁵

Summary

The drupe pistachios are made up of a variety of nutrients and other components that provide a wide range of health benefits such as improving heart health, contributing to a healthy microbiota and preventing diseases such as cancer and cardiovascular diseases. Therefore it is crucial to include pistachios in our diets by eating them roasted or incorporating it in starters, desserts and baked goods. However, it is important to not consume them in excess as it may lead to unwanted side effects.