How does zinc affect your eyes?

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Health Advisor
Ask Felicity

25 July 2018

Why is zinc so important for your eyes?

When it comes to minerals, you’re probably more familiar with the functions of magnesium or the consequences of iron-deficiency – zinc isn’t always top of mind which is a real shame as this nutrient is essential for a number of bodily functions. Your immune system, for example, relies on zinc as it acts as a natural antioxidant and anti-inflammatory agent, helping to prevent colds and flus.1  

Another area of the body that zinc helps to support is your eyes. Did you know that is found in high concentrations in your eyes? It tends to be concentrated in the vascular layer of tissue just below your retina and actually helps to transport vitamin A from your liver to this area, allowing your eye to produce melanin, a protective pigment that actually determines your eye colour! In fact, science has proven that there’s even a link between zinc deficiency and poor night vision.

Studies have also indicated that zinc may play a valuable role in preventing Age-Related Macular Degeneration (AMD). One study funded by the National Eye Institute found that taking zinc alongside other antioxidants could lower the risk of developing AMD by about 25%.2 It worth noting that in another study lower levels of zinc were also combined with beta-carotene, lutein and zexananthin (very similar to the nutrients found in our Vision Complex!) to identical results.3  

So, if zinc is associated with so many benefits for your eyes, why do some experts appear to caution using zinc supplements?

What are the side effects of too much zinc? 

Zinc deficiency is a real problem, especially as it’s associated with so many negative side effects. However, while most people focus on whether or not they’re getting enough zinc, they ignore a key problem that’s now becoming more commonplace – getting too much zinc.

Now you might be thinking that surely, when it comes to vitamins and minerals, it’s a case of ‘the more, the merrier?’ Well not always and thanks to the rise of highly concentrated supplements, having an intake of zinc that’s too high is becoming a problem. When you’re getting too much zinc, not only will it cause side effects such as diarrhea and stomach cramps, it can also influence how you absorb certain nutrients, such as copper or even cause the destruction of healthy retinal cells.4 

How much zinc should you be getting?

Okay, so too much zinc can damage your retinal cells but not enough zinc can also impact your vision. In that case, how much zinc should you be getting? Well, the NHS does have guidelines and recommends that women should get around 7mg of zinc a day while men should be aiming for 9.5mg.5  

Ideally this zinc should be sourced from your diet; however, these figures don’t really take specific circumstances into account. If you’re vegetarian or vegan, for example, sourcing zinc from your diet can sometimes be tricky while sufferers of digestive disorders like Crohn’s can affect how you absorb certain vitamins and minerals. It’s also worth noting that your demand for zinc can also fluctuate, particularly if you’re a woman - for example, teenage girls sometimes need slightly more zinc. 

In these instances, supplementing with zinc can be a good idea – just make sure your supplement doesn’t contain more than 25mg of zinc or you could be risking some of the side effects associated with getting too much zinc. 

What can you do to increase your intake of zinc?

As I’ve mentioned, ideally you should turn to your diet for your daily intake of zinc and not rely on supplements to get this mineral. However, knowing which food sources are rich in zinc can be tricky, particularly if you’re vegan or vegetarian. That’s why below I’ve listed 5 of my favourite vegan-friendly sources of zinc below along with a few tasty recipes to help inspire you!

1 – Pumpkin seeds

Did you know that just one tablespoon of pumpkin seeds can provide you with almost 1mg of zinc?6 Pumpkin seeds are a fantastic source of this mineral as well as another eye-boosting nutrient, omega-3! This makes them a great option if you’re looking to increase your intake of zinc and, since they’re incredibly versatile, you can enjoy them in a wide range of dishes as I detail below!

My favourite pumpkin seed recipes:

Potato Bake with Avocado, Mushrooms & Seeds

Pumpkin Spice Breakfast Bars

2 – Cooked quinoa

Quinoa is a gluten-free seed that is often treated as a grain. In recent years, the popularity of quinoa has soared and for good reason – this pseudo cereal is rich in protein and fibre, as well as containing around 13% of your daily zinc intake, in addition to other minerals such as magnesium and iron. As an added boost, quinoa also contains a plethora of antioxidants that may help to protect your eyes from scavenging free radical molecules!

My favourite quinoa recipe:

Quinoa Stuffed Avocados

Quinoa & Black Bean Mexican Burgers

3 – Hemp seeds

The health benefits of hemp seeds are finally starting to gain some traction, which is just as well as these seeds are super dense in nutrients, containing generous amounts of omega-3 and omega-6 fatty acids! It also helps that they’re brimming with zinc too, with three tablespoons containing around 23% of your daily zinc intake! However, if you’re also interested in increasing your intake of magnesium, hemp seeds might still be a good idea as the same amount contains a whopping 48% of your daily recommended intake!

My favourite hemp seed recipe

Sundried Tomato & Hemp Quiche

4 – Legumes

Okay, so this one might be a bit of a cheat but did you know that legumes like lentils and chickpeas are great sources of not only zinc, but protein too? Protein is actually very important when it comes to zinc as it can help to increase its absorption, allowing your body to better utilise the mineral. The only problem with legumes is that they also contain phytates, which can sometimes inhibit the absorption of zinc - fortunately, cooking methods such as soaking or heating can help to improve the bioavailability of zinc.7 

My favourite legume recipes:

Spicy Tomato & Red Lentil Soup

Homemade Protein Packed Chickpea & Lentil Hummus 

5 – Cashews

Cashew nuts are an excellent source of healthy fats, as well as copper and zinc. Earlier in this blog, I mentioned that zinc can sometimes inhibit your body’s absorption of copper, which is why it’s often a nice idea to take the two minerals together. In this instance, a quarter cup of cashews contains around 21% of your daily zinc intake as well as an incredible 98% of your copper intake! Amazing! It also helps that cashews are very adaptable and can be used in everything from sweet dishes to savoury. 

My favourite cashew recipes:

Coconut & Cashew Amazeballs

Cashew & Banana Smoothie

What if I do need to try a supplement?

Okay, so you’ve tried to increase your dietary intake of zinc but you still feel as though you’re falling short – at what point does it become necessary to consider a zinc supplement? Well, if you’re interested in zinc primarily to support your eye health, you could try a combination of eye-boosting nutrients such as zinc and carotenoids like lutein and zexananthin.

Fortunately, you can find such a combination in our Vision Complex. Not only does this supplement contain zinc, lutein and zexananthin, it also contains beta-carotene and, more importantly, marigold extract! If you’ve read my blog, ‘Trust me…I’m Vision Complex,’ you’ll already have an idea of just how essential this ingredient is for healthy eyes!

However, if you’re interested in a general zinc supplement for your overall health, it’s important that you consider what I mentioned earlier – no more than a 25mg dose! 








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