We've Been Eating Strawberries All Wrong...
Could there be more benefits from consuming the leaves?
It’s difficult to resist a perfectly ripe strawberry; in fact they’re one of the most popular berry fruits in the world. But the widespread consumption may also come with a lot of waste. Each year tonnes of strawberry leaves and tops are discarded and considered as food waste.
Food waste is a serious problem, with three major WRAP studies published in 2013 and 2016 estimating that 85% of the avoidable food waste arises in households and food manufacture. 1
Whilst society has drilled into us that we should only enjoy the red fleshy part of strawberries, the roots, tops and leaves are all edible and may even come with some exciting health benefits...
A rich source of antioxidants
Strawberries are a rich and diverse source of antioxidants. However, what’s less well known is that strawberry leaves may contain even more antioxidants than the red fleshy part.
One study which looked at the fruits and leaves of blackberries, strawberries and red and black raspberries concluded that the ORAC value of the leaves was drastically higher. ORAC values are a measure of the antioxidant capacity of different foods. However, it’s important to note that as leaves become older, the ORAC value decreases which indicate that fresh strawberry leaves may provide the highest antioxidant value. 2
Regular consumption of antioxidant rich foods may protect the body from damage caused by harmful molecules called free radicals. Common sources of free radicals include pollution, sunlight, smoke and even prolonged exercise.
Support the immune system
Not only is the whole strawberry rich in plant antioxidants, but the red fleshy part is also extremely rich in the antioxidant vitamin C.
In fact, eating just 8 strawberries (80g) can provide as much as 115% of your daily vitamin C intake (British Nutrition Foundation). Many associate oranges with vitamin C, but strawberries are actually a higher source per 100g.
Vitamin C contributes to the normal function of the immune system and the reduction of tiredness and fatigue.
May help with blood sugar regulation
Research suggests that consumption of strawberries alongside a carbohydrate-rich meal may reduce its effect on blood sugar and insulin levels. 3
Improving blood sugar control and insulin sensitivity can be a helpful aspect for preventing metabolic syndrome and type 2 diabetes.
Whilst it’s not clear as to why strawberries may have this blood sugar balancing effect, some studies have suggested that it may be down to their rich content of polyphenols (antioxidants), which may influence carbohydrate digestion and absorption.
May have antimicrobial effects
One study analysed the leaves of two hundred strawberry plants and found that their large and diverse range of polyphenols are defensive against harmful microbes, and may even have benefit to human health. 4
Whilst these results are certainly exciting, much more research into strawberry leaf polyphenols in relation to human health is required.
They may improve heart health
Numerous studies have found an association between strawberry consumption, and improved cardiovascular health. It appears the high content of berry anthocyanins may play a role in reducing inflammation and oxidative stress, blood pressure and even improving our cholesterol profile.
In contrast to the fleshy red fruit, strawberry leaves have been largely overlooked when it comes to the health benefits. Whilst it’s too early to state if strawberry leaves can lower blood pressure, one promising study showed potential vasodilatory effects. This study used water extracts of the strawberry leaf and showed an improvement in blood flow within isolated animal aortic rings. 5
They may aid with digestion
Folk medicine has traditionally used an infusion of strawberry leaves to treat diarrhoea and indigestion. Interestingly there is now preliminary evidence to support this use. One study looking at wild strawberries found that the leaves were a rich source of tannings. Tannin-rich plants have been commonly studied for potential anti-diarrhoea activity. 6
May support weight management
Strawberries can satisfy any sweet craving, yet are surprisingly low in sugar and calories. With just 6g of sugar and 33 calories per 100g, they can provide the sweet fix we desire whilst keeping our waistlines trim.
And for an even more indulgent option, try dipping strawberries into antioxidant-rich dark chocolate and coconut flakes.
How to include strawberry leaves in your diet and reduce wastage:
- Add to juices and smoothies
- Strawberry leaf tea – using the stalks and leaves – leave to brew for a few minutes in boiling water
- Vinegar – soak the berries, including the tops, in vinegar (balsamic works especially well) for at least 48hrs, then to add to salads etc
- Infused water - add sliced strawberries and their leaves to water and leave to infuse
- Add to strawberry compote for puddings or breakfast topping
- Strawberry leaf kombucha
Lily Soutter BSc (hons) Human Nutrition, Dip ION
http://www.seasonalberries.co.uk
REFERENCES
- http://www.wrap.org.uk/sites/files/wrap/Estimates_%20in_the_UK_Jan17.pdf
- http://pubs.acs.org/doi/abs/10.1021/jf9908345
- https://www.ncbi.nlm.nih.gov/pubmed/23365108
- http://pubs.acs.org/doi/abs/10.1021/jf405589f?src=recsys&journalCode=jafcau
- http://www.sciencedirect.com/science/article/pii/S0944711308002171
- https://www.researchgate.net/publication/215761887_Chemistry_of_the_Chilean_Strawberry_Fragaria_chiloensis_spp_chiloensis_Gene_Genome_and_Genomics
