Reduce the risk of viruses with Vitamin D3

Jump to Chinese version 跳至中文版

Experts are advising the best way to protect against coronavirus is to reduce exposure, practice good personal hygiene, and support a strong immune system. A proven way to improve immunity, especially against colds, flus, and severe respiratory tract infections, is Vitamin D3.

Why Vitamin D3?

Vitamin D3 (the ‘sunshine vitamin’) works by increasing our levels of secretory IgA – the first line of immune defence against viruses and bacteria. Found naturally in our bodies, Vitamin D3 is produced when sunlight hits our exposed skin. There is a little Vitamin D3 in some foods, but the diet can never provide the sufficient amounts – we need direct sun exposure on the skin, or to supplement the vitamin D3, especially in the winter.

Studies show that people with optimal levels of Vitamin D3 get approximately 40% less respiratory tract infections. Unfortunately, studies also show that an estimated one billion people worldwide have Vitamin D-deficiency or insufficiency.

Do you have enough Vitamin D3?

Closer to home, an alarming 72% of Hong Kongers aged 18-26 years are Vitamin D-deficient, according to research published in 2018. As people age, they’re likely to spend less time in the sun, which means they will have even lower levels of Vitamin D.

Lots of time spent indoors, slathering sunscreen on our skin when we do go out, and nutrient-poor foods can leave us deficient in Vitamin D3 all year round. In the winter months – when we need approximately 45 minutes of exposure to the sun on the arms, legs, face, and hands every second day to achieve optimal levels of Vitamin D3 – getting enough sunlight becomes even more challenging. It’s no wonder we are more susceptible to viruses at this time.

At IMI, our clinical observations concur with the plethora of studies on Vitamin D-deficiency. In initial blood tests, almost all of our clients had sub-optimal levels of vitamin D.

How can you increase your levels of Vitamin D3?

Ideally, we would have more time with our skin exposed to the sun, but this isn’t always achievable.

Fatty fish like salmon, tuna and mackerel, are good sources of Vitamin D, as is pharmaceutical-grade cod liver oil. Small amounts of vitamin D are also present in beef liver, cheese, and egg yolks.

Selected Food Sources of Vitamin D

Food IUs per serving*
Cod liver oil, 1 tablespoon may contain 1,360
Swordfish, cooked, 3 ounces 566
Salmon (sockeye), cooked, 3 ounces 447
Tuna fish, canned in water, drained, 3 ounces 154
Milk, nonfat, reduced fat, and whole, vitamin D-fortified, 1 cup 115-124
Sardines, canned in oil, drained, 2 sardines 46
Liver, beef, cooked, 3 ounces 42
Egg, 1 large (vitamin D is found in yolk) 41
Ready-to-eat cereal, fortified with 10% of the DV for vitamin D, 0.75-1 cup 40
Cheese, Swiss, 1 ounce 6

* IUs = International Units.

However, diet alone simply cannot provide the levels of Vitamin D our bodies need for optimal health. A minimum daily level of 600IU may be sufficient for some people, while others have genetics which need more. To raise low blood levels of vitamin D with supplements requires 2,000IU and more daily to be effective.

Should you take Vitamin D3 supplementation?

Occasional doses of vitamin D can reduce the risk of upper respiratory tract infection by 36%, while daily doses can reduce the risk by 49%, according to a group of 25 studies covering almost 11,000 people from birth to 95 years of age across 14 countries on four continents. Published in the British Medical Journal in 2017, the study concluded: “Vitamin D supplementation was safe and it protected against acute respiratory tract infection overall. Patients who were very vitamin D deficient and those not receiving bolus (one off) doses experienced the most benefit.”

There is also compelling evidence to prove Vitamin D3 supplementation can significantly benefit those with chronic lung conditions, as well as those with asthma. A team of researchers in the UK found seven trials involving 435 children and two studies, involving 658 adults. The majority of people recruited to the studies, had mild to moderate asthma, and a minority had severe asthma. Most people continued to take their usual asthma medication while participating in the studies, which lasted for between six and 12 months. Giving an oral vitamin D supplement reduced the risk of severe asthma attacks requiring hospital admission or emergency department attendance from 6% to around 3%. It also reduced the rate of asthma attacks needing treatment with steroid tablets.

Another large study of a chronic lung condition, COPD, showed similarly impressive reduction in respiratory tract infections when taking Vitamin D daily. It seems the very people most susceptible to severe risk with infections are well protected with Vitamin D3 supplements.

It’s important to note, however, that not all supplements are created equal. Regular daily vitamin supplements do not provide sufficient Vitamin D to meet optimal needs, according to a 2011 study of over 3,000 volunteers in the US. Despite taking regular daily vitamin supplements, 90% of those studied were still sub-optimal in vitamin D.

Here in Hong Kong, the law limits the per tablet or dose delivery to 1,000IU. This is inadequate to raise a low vitamin D blood level efficiently; it is adequate if taken long term to prevent low levels.

IMI’s Supplement Recommendations

Most Vitamin D experts recommend blood levels of 30-60ng/mL. At IMI, our goal is to help you achieve healthy blood levels of 50ng/mL.

Based on research studies, IMI recommends the following supplementation:

Daily doses of 600 – 800 IU for infants under 1, given daily. Both the United States and Canada mandate the fortification of infant formula with vitamin D: 40–100 IU/100 kcal in the United States and 40–80 IU/100 kcal in Canada, and the ranges are similar here. Please note: if supplementing infants with extra vitamin D, take the amounts in formulas or dairy products into account. Over 1,500IU in infants is potentially harmful taken over longer periods.

1,000 – 1,500 IU for 1-14 year olds, given on days there is no time in the sun. This can be taken through the winter months, and discontinued once children are playing outdoors again.

2,000 IU  for age 14 to adult, especially during the winter months to strengthen immunity.

However, during the first week of school after the winter break, Senior Naturopath Graeme Bradshaw recommends 2,000 IU for children and 5,000 IU for adults for a quicker immune effect.

“These dosages, taken for 2-3 months are safe. An initial loading dose is nearly always required in winter, unless there has been a holiday in the sun when blood levels may be higher. If parents wish to be more accurate with dosing, we can test your child’s Vitamin D blood levels with a simple and accurate blood test. If levels are under 30 ng/mL, sun or supplementation is advised. We reduce, though do not stop supplementing, at 50 ng/mL.”

Adequate levels can be achieved through Vitamin D3 supplements that are better absorbed by the body. Store-bought standard capsules do not provide the most absorbable form.

We recommend NanoCelle™ D3 + K2. Shown to quickly improve blood levels, this supplement provides 1,000IU vitamin D with vitamin K in a very effective, highly absorbable spray format.

Some children may prefer Bioceuticals D3 Drops Forte, an easy-to-take vanilla-flavoured liquid supplement that provides 1000IU per drop.

Would you like to know your Vitamin D3 levels?

Our naturopaths can offer a simple pin prick test to confirm your Vitamin D3 levels. If you are deficient, we can recommend appropriate supplementation to ensure you achieve the appropriate level of support. While insufficient levels of Vitamin D3 can undermine your immunity, too much of this vital nutrient can cause side effects like nausea, vomiting, stomach pain and irregular bowel movements. We believe it’s best to test, not guess.

To arrange an in-person or phone/video/Skype appointment with one of our naturopaths at this time, please call (852) 2523 7121 or contact us here. Our range of Vitamin D3 supplements is also available at our dispensary, where you can purchase in-person or online.



專家建議,預防冠狀病毒的最佳方法是減少感染暴露的機會、保持良好的個人衛生習慣和增強免疫力。 維他命D3能有效提高免疫力,尤其是針對感冒、流感和嚴重呼吸道感染。


維他命D3(「陽光維他命」)的作用是提高我們分泌型免疫球蛋白A (secretory IgA)的水平這是抵抗病毒和細菌的第一道防線。 維他命D3是經由陽光照射皮膚而合成的, 只有少部分是從食物中攝取,但是飲食永遠無法提供足夠的維他命D3 。尤其是在冬天,我們需要直接讓身體接觸陽光,或服用維他命D3補充劑,才能攝取足夠的維他命D3




外出時,我們會花大量時間在室內且陽光不足的地方、塗上防曬霜或長期進食營養不良的食物會使我們全年缺乏維他命D3。 在冬季,我們每隔一天便需要讓身體(手臂、腿、臉和手)接觸陽光以達到最佳維他命D3含量水平。因此獲得足夠的陽光就變得更具挑戰性, 難怪我們現在更容易感染病毒。

IMI,我們的臨床觀察與有關維他命D缺乏症的大量研究一致。 在最初的血液樣本檢查中,幾乎所有客戶的維他命D含量都不理想。



鮭魚、金槍魚和鯖魚等含豐富脂肪的魚類和魚肝油是維生素D的良好來源。 少量維生素D也存在於牛肝,奶酪和蛋黃中。


食物 每份食物IU *
魚肝油(一湯匙) 1,360
煮熟的箭魚(3盎司) 566
煮熟的鮭魚(大眼)(3盎司) 447
吞拿魚罐頭(去水)(3盎司) 154
牛奶(脫脂、減少脂肪和全脂),強化維他命D(1) 115-124
油浸罐頭沙甸魚(瀝乾)(2) 46
煮熟的肝、牛肉(3盎司) 42
雞蛋(1)(蛋黃中含有維他命D) 41
即食穀物,含每天建議量10%的強化維他命D (0.75-1) 40
瑞士芝士(1盎司) 6

*IUs =國際單位。

但是,單靠飲食根本無法提供人體最佳健康所需的維他命D。 對於某些人來說,最低每日600IU的水平可能巳經足夠,但另一些人的體質則需要更多。 所以要通過營養補充品來提高血液中維他命D的含量,每天需要2,000 IU或以上的劑量才能有效。


根據一組含有25項研究,覆蓋四大洲內14個國家,將近11,000名從初生嬰兒到95歲的人群中,研究顯示,偶爾服用維他命D可將上呼吸道感染的風險降低36%,而每日服用則可將這風險降低49%。  該項研究於2017年發表在《英國醫學雜誌》上,得出的結論是:補充維他命D是安全的,並且可以全面預防急性呼吸道感染。 維他命D缺乏症嚴重且未接受注射(一次性)劑量的患者獲益最大。

另外,補充維他命D3可有效幫助患有慢性肺病以及患有哮喘的人。 英國的一項研究進行了7個試驗,涉及435名兒童,其中兩項研究涉及658名成人。 參加這項研究的大多數人患有輕度至中度哮喘,少數人患有嚴重哮喘。 大多數人在參加研究期間繼續服用一般的哮喘藥物。持續了612個月。 口服維他命D營養補充劑可將需要住院或急診就診的嚴重哮喘發作風險從6%降低到3%。 並降低了需要使用類固醇片劑治療的哮喘發作比率。

另一項針對慢性肺部疾病的大型研究(COPD)顯示,每日服用維他命D可以顯著減少呼吸道感染。 所以維他命D3營養補充品可以保護最容易受到嚴重感染風險的人。

需要特別注意的是,並非所有營養補充品都是一樣的。 根據2011年美國3,000多名志願者的一項研究顯示,每天定期補充的維他命並不能提供足夠的維他命D來滿足最佳需求。 儘管每天定期補充各種維他命,但90%的被研究者維他命D含量仍不理想。

在香港,法律將每片或每劑的劑量限制為1,000IU。 這不足以有效地提高血液含量內維他命D的水平; 需要長期服用才能確保足夠攝取。


專家建議血液中維他命D含量為30-60ng / mL。 在IMI,我們的目標是幫助您達到50ng / mL的健康血液含量水平。


1歲以下嬰兒的每日維他命D攝取量為600 – 800 IU,每天給予一次。 美國和加拿大都要求使用維他命D強化嬰兒食品配方:美國為40–100 IU / 100 大卡(kcal),加拿大為40–80 IU / 100 大卡(kcal)。敬請留意:如果要向嬰兒補充額外的維他命D,需考慮到配方奶粉或奶製品中的含量。 長期服用1,500IU以上可能對嬰兒有害。

114歲的兒童每日維他命D攝取量為1,000 – 1,500 IU,可於沒有接觸陽光的日子補充。 亦可以在整個冬季進行。一旦孩子在戶外玩耍並接觸陽光,便可以停止服用。

14歲至成人每日維他命D攝取量為2,000 IU,尤其是在冬季,以增強免疫力。

但是,在寒假後回復正常工作和開學的第一周,自然療法師Graeme Bradshaw建議為兒童提供2,000 IU,為成人提供5,000 IU的維他命D攝取量以提升免疫效果。

「於2-3個月內服用這些劑量是安全的。 在冬季,除非能確保身體接觸足夠陽光,血液水平可能會提高,否則便需要初次負荷劑量。 如果父母希望用藥更準確,我們可以通過簡單而準確的驗血測試,從而了解孩子的維他命D血液含量水平。 若水平低於30 ng / mL,建議日曬或使用營養補充品。 但不要停止補充,建議最好維持在50 ng / mL。」

通過服用維他命D3營養補充品可以達到足夠的水平,更好地被人體吸收。 但於商店購買的標準膠囊無法提供最易吸收的形式,因此我們建議使用NanoCelle™D3 + K2。 該營養補充品可以快速改善血液含量水平,非常有效,並且以高度吸收的噴霧形式提供1,000IU維他命D和維他命K

小孩可能更喜歡Bioceuticals D3 Drops Forte,這是一種易於服用的香草味的維他命D3滴劑,每滴可提供1000IU


IMI的自然療法師可以提供簡單的點刺測試,以量度你的維他命D3水平。 如果你身體較為虛弱,我們建議你進行適當的營養補充,以確保身體獲得適當的支持。 雖然維他命D3含量不足會損害你的免疫力,但攝取過多會引起噁心、嘔吐、胃痛和排便不規律等副作用。所以最好先進行測試,而不是猜測。

現時,我們的自然療法師可作親自或通過電話/視像/ Skype等方式為你診症,請致電(852) 2523 7121在此處與我們聯繫。 我們的藥房提供了一系列的維他命D3營養補充劑,你可以蒞臨本店或 IMI 網上營養補充品店選購。


Share via
Copy link
Powered by Social Snap