The Sydney-based company declined to comment on the buyout price, but revealed that the current owners, the Wu family, would retain a significant stake.
Estimates from industry sources, however, have placed the buyout price at almost A$800m.
JIC Investments is a wholly owned subsidiary of the state-run sovereign fund China Jianyin Investment Ltd, and Tamar Alliance Fund belongs to CITIC Pacific, which itself is a wholly owned subsidiary of the Hong Kong-listed CITIC Ltd, China's largest conglomerate.
Nature's Care CEO Tom Coleman — who took over in December 2017 and was previously CFO at Swisse Wellness — said the buyout was expected to increase distribution in China, where the company has been targeting higher-end customers.
He told national media that the new owners would bring "capability and networks that we wouldn't otherwise have. The pace we've been moving at was already very fast".
This was the Wu family's second attempt at a sale. After an unsuccessful first attempt in 2016, it announced in November last year that it was looking for buyers again, shortly after announcing its intention to launch an IPO and be listed on the ASX in 2018.
Since January this year, there had been speculation as to which firms were interested in Nature's Care, with both CITIC and JIC among the potential buyers.
With approximately 7% share of Australia's vitamin market, just behind the respective 20% Swisse and Blackmores have, Nature's Care is considered the country's third largest vitamin company.
It recorded close to A$60m in earnings for the 2017 financial year, and attracts yearly revenues of over A$230m. Its Healthy Care brand is responsible for around 90% of its sales, which has increased by 23% annually for the past three years.
Coleman said that among the Chinese middle class, premiumisation is growing more popular, evidenced by greater demand for Nature's Care's Pro-Series range of supplements.
Since 2014, Chinese demand for supplements and vitamins from renowned Australian and New Zealand brands has grown, thanks to the latter's reputation as a safe, clean and sustainable source of health-boosting products.
This has led to numerous Chinese buyers acquiring Australian firms, including Shanghai Pharmaceuticals' takeover of Vitaco in 2016, and more recently, BY-HEALTH's purchase of Australian probiotic firm Life-Space.
The biggest deal so far, however, was Health & Happiness' (formerly Biostime) acquisition of Swisse for A$1.69bn in 2016.
KPMG analysts have predicted that Chinese investment in Australian firms will continue to increase, amid China's maturing healthcare system and ageing population.