Anthocyanin antioxidant activity of NZ blackcurrants

What does high anthocyanin antioxidant activity of NZ blackcurrants mean for our health?

Dr Carolyn Lister of the New Zealand Institute for Crop and Food Research has shown that premium New Zealand blackcurrants have a higher total antioxidant activity than the European bilberry, which has often been reported as having the richest antioxidant levels of fruit worldwide.

The New Zealand blackcurrant is a powerhouse of antioxidants, with an antioxidant level of 7600umol TEAC per serve compared to blueberries at 5200 umol TEAC per serve.

Anthocyanins in blackcurrants

Much of the antioxidant activity is based around the coloured compounds in the blackcurrant – the intense rich black-red, supplied by the anthocyanins. New Zealand varieties contain as much as 700mg/100g fresh fruit. This compares very favourably with many blueberries at around 100-200mg/100g.

What do Anthocyanins mean for human health?

The health benefits of blackcurrants have long been attributed to their high levels of Vitamin C. Research over the last 20 years indicates there may be more to the story, including the contribution of the high antioxidant activity and anthocyanin content of blackcurrants. Significant health benefits have been indicated by ongoing research into the effect of anthocyanins. These include potentially preventing various types of degenerative ailments such as heart disease and cancer, slowing down the aging process, and protecting the body’s vision and neurological functions.

According to the 2004 research paper – ‘Anthocyanins – More than Nature’s Colour’ by Izabela Konczak and Wei Zhang, anthocyanins were incorporated into the human diet many centuries ago. They were components of the traditional herbal medicines used by North American Indians, the Europeans and the Chinese. Derived from dried leaves, fruits (berries), roots and seeds, anthocyanin-rich mixtures and extracts have been used historically to treat conditions as diverse as hypertension, liver disorders, dysentery and diarrhoea, urinary problems including kidney stones and the common cold. They have also been linked to improvement in vision and blood circulation.

Potential potency of the anthocyanins backed up by research

Other studies using purified anthocyanins or anthocyanin-rich extracts have confirmed the potential potency of these pigments. Demonstrated possible benefits include protection against liver injuries, significant reduction of blood pressure, improvement of eyesight, strong anti-inflammatory and antimicrobial activities, inhibition of mutations caused by mutagens from cooked food, and suppression of proliferation of human cancer cells. Along with other phenolic compounds, they are potent scavengers of free radicals, although they can also behave as pro-oxidants.

Because of their diverse physiological activities, the consumption of anthocyanins may play a significant role in preventing lifestyle-related diseases such as cancer, diabetes and cardiovascular and neurological diseases.

Anthocyanins and vision

Japanese studies indicate that blackcurrant anthocyanin concentrate has significant and beneficial effects on vision. The rapid spread of computers in the home and workplace has led to an increase in eye discomfort, blurring of distant objects, eye strain, and visual fatigue. A study to measure the improvement in eye function after taking blackcurrant anthocyanin supplements has shown improved ability to adapt to darkening light conditions and counteraction of the transient myopic shift of refractive status (the most reliable indicator of visual fatigue) after visual tasks such as computer operation. Subjectively participants noted significant reduction in eye discomfort.

The powerful antioxidant group of anthocyanins, found in high amounts in NZ blackcurrants have many potential health benefits warranting further ongoing NZ and international research.

Sources
  • He, J., & Giusti, M. M. (2010). Anthocyanins: natural colorants with health-promoting properties. Annual review of food science and technology, 1, 163-187.
  • Konczak, I., & Zhang, W. (2004). Anthocyanins-more than nature’s colours. BioMed Research International, 2004(5), 239-240.
  • Nakaishi, H., Matsumoto, H., Tominaga, S., & Hirayama, M. (2000). Effects of black currant anthocyanoside intake on dark adaptation and VDT work-induced transient refractive alteration in healthy humans. Alternative Medicine Review, 5(6), 553-562.

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