Should I avoid canned fruit?
Q: Is canned fruit still healthy or should I avoid this? Many thanks, Maryanne
A: When it comes to fruit, I prefer to encourage choosing fresh or snap frozen where possible. During the canning process, the fruit is heat treated, which is necessary from a food safety perspective as it kills any organisms present, but it also destroys some nutrients, particularly vitamin C, as well as inactivating enzymes that are naturally present in the fruit.
When fruit is canned it is usually bathed in either syrup or fruit juice (both of which add sugar), and the fruit can absorb some of the sugars from these.
Canned fruit may also contain other additives such as preservatives, so it’s a good idea to check the label. If you can, choose fresh or frozen.
Nutrient losses can occur as fruit ages, so for optimal nutrition (and taste!) choose local produce that is in season. This is a great way to support your local farmers and minimise food miles, too.
I also like to encourage people to think about the packaging. A tin can – and most are lined with plastic – can take anywhere from 20 to 200 years to break down. So fresh is always best.
If you love tinned fruit and it nourishes you, it’s best to drain the juice and be sure to amp up your intake of vitamin C-rich vegetables (such as broccoli, cauliflower, capsicum and kale) to ensure you are meeting your vitamin C requirements.
Q: I’ve read that zinc is good for your skin. What foods are best to eat for zinc? Erin
A: That’s right, zinc is one of the key nutrients for great skin health. It is critical for wound healing, whether it’s a cut we need to heal or the aftermath of a pimple, and its role in protecting against damage from free radicals also makes zinc an essential nutrient for anyone who wants to prevent premature ageing of the skin.
The best food sources of zinc are oysters from clean waters, liver, beef, pumpkin seeds and sunflower seeds, and smaller amounts are also found in other seeds, nuts, lentils, chickpeas and eggs.
There are, however, some substances that can interfere with the absorption of zinc in the body. Other nutrients such as copper and calcium can negatively affect absorption, so having calciumrich foods at a different time to your zinc food sources may help to maximise your zinc absorption. Fibre can also inhibit absorption, so if you take a zinc supplement it’s best to take this away from food. Just before bed is a good time.
Tannins in tea and coffee bind
zinc which can prevent it from being absorbed in the body, so it’s important to avoid drinking tea and coffee with your meals. Adopting a habit of drinking any beverages or water between meals rather than with your meals also helps to support optimal stomach pH.
The stomach is supposed to be extremely acidic – we need the pH to sit at around 2. Water has a pH of 7 (neutral pH) or greater so drinking water with meals may potentially dilute your stomach acid. Supporting optimal stomach pH is important for overall digestive function, and it also benefits zinc absorption as this is known to be enhanced in an acidic environment.
❚ Dr Libby is a nutritional biochemist, best-selling author and speaker. The advice contained in this column is not intended to be a substitute for direct, personalised advice from a health professional. See drlibby.com