I had planned this article (video) on Watermelon on Monday when we were having gorgeous warm weather here on the coast. It was 33c and I was sitting on the beach soaking up the rays. Ever since it’s been overcast and mid 20’s. Still I think with the warm weather approaching us here down under it’s the perfect time to dive into Watermelon.

What’s in watermelon?

Main form of macro nutrient is carbohydrate in the form of primarily in the form of fructose and sucrose. It packs a hearty 21% of our vitamin C requirements and 18% of our vitamin A. The majority of watermelon is not surprisingly water and also has a great serving of potassium [1].

This is another one of our high antioxidant foods, helping protect our cells from free radicals. Are you guys beginning to notice a trend… So many of our vegetables and fruits have these compounds in them that’s why we need to get plenty of them in our diets. The antioxidants in watermelon are our vitamin C and vitamin A. There is also a phytochemical, that is a plant chemical, lycopene, a caritoniod. It gives watermelon but also tomatoes, guavas, pink grapefruit their red and pink colours. Much like our berries a couple of weeks ago, with their anthocyanins, these antioxidants can help mop up those pesky free radicals that rust our cells and takes it’s toll on our bodies.

Watermelon: Sun protection

Protecting the skin. I don’t know about you but there is something about being at the beach or in the pool in summer time that makes me crave watermelon. Turns out this could very well be an evolutionary craving from our body to help protect us from the sun. Sunscreen hasn’t always been available to us so our bodies have had to find ways to protect against the damage sun can cause. Cue lycopene, vitamin A. Lycopene has been found to increase photoprotection of the skin. Now I’m not saying don’t protect yourself from the sun, but a little added help from within certainly helps.

Studies [2] have been conducted showing that carotenoids – lycopene and vitamin A (B-carotene) have had positive effects of sun damage – namely sunburn on the skin. Results showed those having a diet rich in lycopene and vitamin A had a modest protection against UVA and UVB induced sun burn. The increase in protection was 1.5x higher than before eating the lycopene and vitamin A foods. It was also shown that this protection is dependent on duration and dose of the carotenoids. The dose of carotenoids needs to be above 12mg/day for a minimum of 7 weeks. This is why I thought I’d better dive into this topic. Starting munching down on that watermelon now. Interestingly when taken in a supplement form lycopene did not show the same protection for our skin. Even more reason to just eat real food.

Getting the lycopene bang for your buck.

So the average Australian gets 3.8mg/day, the English 1.1mg. Watermelon contains 4-5mg of lycopene per 100g, with an average watermelon serving being 280g [3]. Just one serve of watermelon a day can give us the 12mg required to see benefits from sun damage. And that doesn’t take into account the vitamin A content which also contributes or other sources such as tomatoes and tomato products, apricots and papaya. We can totally do that!Watermelon, Rocket and Mint Salad

Lycopene is lipid soluble, it needs fat for our body to digest it. So consuming it with fat makes it more bio available – the body can use it better. I know you are probably thinking – fat and watermelon… well you could have it with nuts or seeds as a snack. Pop it into your smoothie with some coconut yoghurt or some nut butter. Or make a refreshing watermelon salad with an olive oil dressing. And there is your fat.

The darker the pink almost red your watermelon is the more lycopene content it will have – so choose fully ripened fruits.

Watermelon: For the athletes

Watermelon is 91% water meaning its a great whole food source of hydration and nutrition. A randomised study of endurance athletes – cyclists – who competed in a 75km time trial on a hilly course [4] was conducted. In the two weeks leading into the time trial subjects consumed 908ml of watermelon puree as a drink. During the time trial they consumed 0.2g/kg of body weight every 15 mins. If you were 80kg this means you would be having 16g every 15mins. The control group did the same but with a carbohydrate sports drink. The antioxidant capacity of the riders post-time trial who consumed the puree was significantly higher than the control group. This improved the post exercise oxidative stress and consequent inflammation in the body. There was no difference in the performance of either group, highlighting that watermelon is a great whole food source of carbohydrate, rather than those processed glucose shots many endurance athletes consume – with the added bonus of that antioxidant kick and l-citrulline.

L-citrulline, an amino acid found in Watermelon can help prevent muscle soreness [5]. A small study was conducted in which athletes consumed watermelon juice over a 24hr periWatermelonod and experienced improvements in blood flow and heart rates that were beneficial for muscle recovery. This is due to its effects on Nitric Oxide. Nitric Oxide allows the 50 trillion cells in our body communicate with each other. Taking L-citrulline for a week has also been shown to increase performance when exercising at a high percentage of VO2 max for 10 mins. This is due to its effects on vasodilation, when our veins dilate, increasing blood flow and mitochondrial work [6,7].

Our blood transports all of the nutrients and oxygen to our organs and muscles and removes all the waste like lactic acid. Having a diluted veins allows the flow of the good stuff to our muscles more efficiently and also removes the waste. This increase in nutrients means those little powerhouse cells our mitochondria can work harder as they are getting more fuel. All this from watermelon.

The potassium content in watermelon also promotes vasodilation and is great for balancing water retention in our guts, helping you keep from dehydrating. So as an athlete you are getting a bigger anti-oxidant hit, helping reduce inflammation, having a wholefood source of carbohydrate for those performance needs, increasing your bodies ability for muscle recovery and energy output at the same time helping your gut retain water…. Why would you not be including this in your race prep.

Picking a watermelon

Heavy for it’s size, deep red colour and the part on the bottom where it’s sat in the field ripening should be a creamy yellow colour – white or green means its may have been picked too soon and not as ripe as it should be

References

[1] Food Standards Australia and New Zealand, NUTTAB.

 

[2] Stahl, W. & Sies, H. (2012). β-Carotene and other carotenoids in protection from sunlight. The American Journal of Clinical Nutrition 96(5), 1179-1184

 

[3] Suwanaruang, T. (2016) Analyzing Lycopene Content in Fruits. Agriculture and Agricultural Science Procedia 11, 46–48

 

[4] Shanely, R.A.,Nieman, D.C., Perkins-Veazie, P., Henson, D.A., Meaney, M.P., Knab A.M. & Cialdell-Kam, L. (2016). Comparison of Watermelon and Carbohydrate Beverage on Exercise-Induced Alterations in Systemic Inflammation, Immune Dysfunction, and Plasma Antioxidant Capacity. Nutrients 8(8), 518.

 

[5] Tarazona-Díaz, MP., Alacid, F., Carrasco, M., Martínez, I. & Aguayo, E. (2013). Watermelon juice: potential functional drink for sore muscle relief in athletes. Journal of Agriculture and Food Chemistry 61(31), 7522-7528.

 

[6] Bailey, S.J., Blackwell, J.R., Lord, T., Vanhatalo, A., Winyard, P.G. & Jones, A.M. (2015). l-Citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans. Journal of Applied Physiology 119(4), 385-395

 

[7] Suzuki, T., Morita, M., Kobayashi, Y. & Kamimura, A. (2016). Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men: Double-blind randomized placebo-controlled 2-way crossover study. Journal of the International Society of Sports Nutrution 13(6)