Kale and Spinach are great, but they come with a health warning

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Sandhya Govind

Sandhya Govind

Auckland, June 29, 2022


                                                                                                                                                                                   Kale and Spinach are packed with nutrients but they can be harmful to some (Healthline Photo)

“We eat with our eyes.”

It is believed that this idea existed as early as the 5th century AD, when it was first mentioned in the Apicius, also known as De re Culinaria  (The Subject of Cooking), one of the earliest European cookery books which contained a collection of ancient Roman recipes.

The visual impact created by a plateful of food is as important as the flavour of the food itself.

And what better way to create a beautiful, colourful plate than to embellish your plate with the colours of the rainbow by using a selection of the wonderful array of colourful fruits and vegetables offered to us by nature?

This is the third of my series of articles on the health benefits that can be reaped by eating fruits and vegetables belonging to different colour groups and this article will look at the different ways in which two important green vegetables, Kale and Spinach, can help us stay healthy and fight illness and will also discuss the precautions that must be taken by people suffering from certain health conditions and on certain medications.


Image from urduesl.com

Kale, a cruciferous vegetable

Kale is a leafy, cruciferous vegetable that belongs to the Brassicaceae or mustard family. Kale has high fibre content and is also a good source of Vitamins C and K, calcium, iron, potassium, phosphorous, the antioxidants alpha-linolenic acid, beta carotene, lutein and zeaxanthin as well as the pigment chlorophyll that is responsible for its green colour

The high fibre content in Kale may reduce our risk of developing Type 2 Diabetes as well as help lower blood glucose levels in people suffering from Type 2 Diabetes. This is because the body cannot break down and absorb fibre, and therefore eating foods with high fibre content will not result in a spike in blood sugar, thereby helping the blood sugar to remain stable.

Similarly, foods rich in fibre are also helpful in weight management because the undigested fibre moves slowly through the stomach keeping hunger at bay. Fibre also helps keep the digestive system healthy by absorbing harmful bacteria and other waste in the digestive system and assisting with their elimination.

A high-fibre diet also helps lower the levels of total cholesterol and low-density lipoprotein (LDL), the harmful cholesterol in the blood.

Research has shown that alpha-linolenic acid could help protect against cardiovascular disease as well as help reduce complications that may occur with Type 2 Diabetes.

Kale is a good source of beta-carotene, a carotenoid that the body can convert into vitamin A whenever necessary. Vitamin A protects the eyes from night blindness and other age-related eye diseases. It can also strengthen the immune system.

Spinach for Vitamins

Spinach is another green leafy vegetable that has an extremely high Vitamin K content. It is also a good source of vitamin A, Vitamin C, vitamin E, folate (Vitamin B9), iron, potassium, manganese, and magnesium.

An important compound present in Spinach, Kale and other green vegetables is chlorophyll. It has been shown that chlorophyll can help prevent the body from absorbing carcinogenic chemicals called heterocyclic amines that are created when meat is grilled at very high temperatures. It can do this by binding to these chemicals, thereby preventing absorption.

Vitamin C is necessary for the formation of collagen and helps maintain cartilage, bones and teeth. It also facilitates the absorption of iron by the body, is essential for the proper functioning of the immune system controls infections and helps heal wounds.

Potassium can help reduce blood pressure and lower the risk of heart disease.

Calcium is necessary to develop and maintain the strength of the bones and teeth. It facilitates muscle contraction, helps the heart, and nerves function properly.

Vitamin K is necessary for the body to be able to produce the proteins prothrombin, essential for blood clotting and osteocalcin, essential for bone formation.

Lutein and zeaxanthin are two carotenoids found in spinach and kale, that synergistically combine in the macula of the eye to block harmful blue light from reaching the retina and causing damage that could result in macular degeneration and cataracts.

Some harmful effects

Though Kale and Spinach are packed with nutrients that offer numerous health benefits, there are certain instances when these vegetables must be taken with caution.

Both Kale and Spinach have extremely high Vitamin K content. Since this vitamin facilitates blood clotting, it can interfere with the effects of some blood thinners. Therefore, people who are on blood thinners or anticoagulant medications should consult with their doctor before including Kale or Spinach in their diet.

The high potassium content of Kale and Spinach means that people who are on beta blockers for heart disease and people suffering from kidney disease should consult with their doctor before including Kale in their diet.

Kale, like all other cruciferous vegetables, contains substances called goitrogens that can interfere with thyroid function and are especially harmful to people who have an underactive thyroid and suffer from hypothyroidism. Goitrogens can block iodine from entering the thyroid gland resulting in a condition called goitre which causes thyroid enlargement. Though cooking can help reduce the goitrogenic property of kale, people suffering from hypothyroidism should treat kale and other cruciferous vegetables with caution.

Spinach contains a large amount of certain naturally occurring compounds called oxalates. Consumption of large amounts of oxalates may result in the binding to calcium and forming kidney stones. In most people, the body naturally gets rid of oxalates but people who suffer from kidney disease or who are prone to kidney stones should consult with their doctor before including spinach regularly in their diet. Special attention should be paid to oxalate consumption when you are on a course of antibiotics, as antibiotics deplete the good bacteria that absorb oxalates in the gut, leading to more oxalates circulating in the system.

Please seek professional advice before making any major dietary changes. This is especially important if you are pregnant, breastfeeding, are already on medication or supplements, or are suffering from any medical condition. Nutritional supplements should only be taken if they are prescribed by a health care professional after a personal consultation. The information provided in this article is not to be used as a substitute for direct medical advice from your doctor, especially if you have any concerns regarding your health.

Sandhya Govind is a qualified and trained Naturopath and runs ‘Sandhya’s Naturopathy Clinic,’ an integrated Natural Medicine facility, which helps people rediscover optimal health, radiance and vitality naturally. Email: sandhyanaturopathy@gmail.com; The above article should be read for general information purposes only and not taken as individual advice. Please always consult your GP or other authorised persons or agencies for personal advice. Indian Newslink and Sandhya Govind absolve themselves of all responsibility or liability in this connection.


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