Many of my friends, myself included, have stepped up our immunity-boosting measures during the pandemic: popping vitamin C supplements consistently. However, a recent YouGov survey commissioned by Zespri, “Nutrition and Vitamin C Matters”, found that one in two Singaporeans (56%) are either unsure or unaware if they are meeting their daily nutritional needs. The nationwide online survey of more than 1,000 adults aged 18 and over covered questions on nutrition and their eating habits.
The survey also showed that Singaporeans still have a long way to go in their awareness of the benefits of vitamin C. For example, while most knew it supported overall immunity, 85% did not know the amount of vitamin C required daily, and 75% did not know that we need to consume it daily because our bodies cannot produce or store it.
I took this opportunity to speak with Dr Verena Tay, a dietitian-nutritionist with more than 15 years of diverse experience spanning clinical nutrition, academia, research and corporate work, to answer our burning questions on all things Vitamin C. I bet there are things you didn't know about Vitamin C. So read on, and our families will benefit from our knowledge too.
At the same time, Yahoo Life Singapore has painstakingly sourced vitamin C supplements with over tens of thousands of review for your convenience. Read on for deets and here's wishing you and your loved ones the best of health in the new year to come!
The ABCs of Vitamin C
Yahoo Life Singapore: What is Vitamin C? And where are the best natural sources of Vitamin C?
Dr Verena Tan: Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. Our bodies do not produce or store this vitamin; hence, it must be replenished daily. Fruits such as kiwifruit, guava, and strawberries and vegetables such as broccoli, capsicums, and cauliflower are great natural sources of vitamin C.
We all know that Vitamin C is an essential nutrient in our bodies, but how does it benefit us? For example, do vegetables offer higher content of Vitamin C than fruits, and does Vitamin C help counteract fatigue?
The body requires nutrients such as vitamin C to perform its functions, including those needed for the immune system.
Vitamin C cannot be stored in our bodies: We need to consume vitamin C daily because our bodies cannot produce or keep this vitamin. Therefore, any excess vitamin C that you eat will leave the body.
Contributes to alleviating feelings of fatigue: The “Nutrition and Vitamin C Matters” survey conducted by Zespri Singapore found that 74% of Singaporeans surveyed did not know that vitamin C contributes to reducing tiredness and fatigue. Evidence shows that when you feel sluggish and easily tired, it could be a symptom of vitamin C deficiency. Vitamin C also activates numerous enzymes in the body and brain chemicals to enhance energy levels.
Contributes to the protection of cells from oxidative stress: Oxidative stress happens when there is an imbalance between the production and accumulation of free radicals in cells and the body’s inability to detoxify these radicals. Vitamin C is an antioxidant that can interact with these free radicals and prevent them from causing damage. However, free radicals are also known to lead to rapid ageing.
Why are there so many different forms of Vitamin C – gummies, chewable, effervescent supplements? Why are some Vitamin C time-released? Which ones should we pick?
Different forms of vitamin C cater to other individuals' needs, depending on age, dietary requirements and health history. For example, a time-release formula allows vitamin C to be released slowly throughout the day. This helps maximise the absorption of the vitamin for those who have trouble meeting their vitamin C needs. Where possible, consuming vitamin C as part of whole food is always preferable because real food offers numerous macro- and micronutrients and phytochemicals, giving additional health benefits.
Is there really a need for Vitamin C supplements for someone who is generally healthy with no known health issues? Is it essential to consume Vitamin C supplements during the pandemic? Is there such as thing as too much Vitamin C?
- You can get your daily requirement of vitamin C from a conscious selection of fresh fruits and vegetables. If you already eat a diet rich in whole foods (fruits, vegetables) which contains sufficient vitamin C, there is no need for supplements. One kiwifruit can provide your daily vitamin C needs.
- The abovementioned survey showed that only 16% have at least one healthy, well-balanced meal daily, and less than half (45%) have them 1 to 3 times a week.
- There is room for Singaporeans to work on eating well to fuel their bodies.
- Excessive amounts of vitamin C from over-supplementation may interfere with certain medications or conditions. For example, ingesting more than 2000mg of vitamin C daily may cause nausea, diarrhoea and kidney stones.
How much is enough? 500mg or 1000mg in a day? And how much Vitamin C is equivalent to 500mg or 1000mg if we are consuming Vitamin C from natural sources? Are there any situations where one may require more Vitamin C daily?
- According to the Health Promotion Board, Singaporeans adults are advised to consume at least 80mg of vitamin C or ascorbic acid daily.
- Some groups are more likely than others to absorb lesser amounts of vitamin C in their diet. As a result, they will require a higher intake of vitamin C. For example, smokers need more vitamin C per day than non-smokers because they have lower levels of vitamin C in their blood than non-smokers because they use it up faster.
- Patients with medical conditions such as diabetes, kidney stones or kidney dysfunction should avoid overconsumption of vitamin C long-term. The use of high amounts of vitamin C supplementation may interact with existing medications and conditions. Consult your healthcare practitioner first, especially if you have any underlying medical conditions.
The volatility of Vitamin C
Is there an optimum time to consume Vitamin C?
This is a common misconception as there is no optimal time to consume vitamin C.
If Vitamin C is easily destroyed, how do we ensure we reap the maximum benefits when consuming them, especially fruits? Do cut fruits have any Vitamin C content left, bearing in mind that Vitamin C oxidises quickly?
Vitamin C is best consumed in raw foods such as fruit as heat and light can destroy the amount of vitamin. However, chilled, ready-to-eat, fresh-cut fruit such as kiwifruit still retains high levels of vitamin C.
You mentioned that one kiwifruit could provide one’s daily vitamin C needs. What is the difference between green vs gold kiwifruits? Which one should I pick?
All Zespri Kiwifruits are rich in vitamin C. It all depends on your preference. While the green kiwifruit has green flesh with black seeds, SunGold Kiwifruits have vibrant yellow flesh with a smaller core and fewer seeds. Green kiwifruit has a fresh, tangy-sweet taste, while SunGold Kiwifruit, unique to Zespri, has a tropically sweet taste. Sweet or tangy – you can pick which suits you best.
Vitamin C content: Based on the recommendation of consuming 80mg of vitamin C daily, eating either Zespri Green Kiwifruit or SunGold Kiwifruit will meet 100% of your daily vitamin C needs. It is a great healthy snack throughout the day.
Is there a specific expiry date for kiwis?
Once ripe, kiwifruits can be eaten immediately or stored in the refrigerator for 7-10 days. To slow the ripening process, keep the kiwifruits separate from other fruit. Kiwifruits sweeten as they ripen and get softer, and it is best to consume them before they become too weak. You can enjoy the fruit by cutting it half and scooping the flesh with a spoon.
Any general tips and tricks for staying healthy during the pandemic?
Maintaining a healthy diet is a great start! Good nutrition and eating habits are crucial to staying healthy during this time. The recent Zespri survey found that Singaporeans consider accessibility and convenience (34%) as the highest priority in selecting a snack. It may be tempting to reach out for unhealthy snacks such as bubble tea, but here are some general suggestions to stay healthy during the pandemic.
Make educated food choices and eat nutrient-dense foods.
Eat fruits and vegetables that help you get your maximum nutrition and daily vitamin needs. Some products offer multiple health benefits within a single piece. A bonus tip is to look for foods with a low Glycemic Index (GI). A Zespri Kiwifruit is a good example. It is rich in vitamin C, contains folate, and is low GI.
Reduce the consumption of red meat and processed meat. Red meat is a source of saturated fat, cholesterol, animal protein and haem-iron (iron-containing substance), while processed red meat has preservatives, additives and chemicals. Both can impact your health.
Cut back on sugary drinks. Your sugar consumption should be at most 10% of your energy intake. Based on a 2000-daily calorie intake, that is about 10 teaspoons of sugar.
About Dr Verena Tan
Dr Verena Tan is an Associate Professor at the Singapore Institute of Technology and an Accredited Dietitian of Singapore (ADS). In 2016, Dr Tan completed her PhD at the Yong Loo Lin School of Medicine at the National University of Singapore on an A*STAR scholarship. Her doctoral research focused on carbohydrate quality and metabolic function. She has since authored over 14 scientific publications and presentations. Dr Verena is passionate about how everyone can cultivate health and well-being through nutrition.
The content on this page is for informational purposes only and is not a substitute for medical advice, diagnosis or treatment. You should always seek advice from a qualified healthcare provider on queries regarding a medical condition. Any action taken by you in reliance on or in connection with this content is solely at your own risk.