Black Currants May Help Fight Glaucoma

The research into the effect of black currants on glaucoma patients is incredibly important because the loss of vision cannot be restored, but successful treatment can prevent it from continuing and worsening. Japanese research shows that glaucoma patients can benefit from supplementing their daily diet with black currants. This same research also indicates that healthy (those without glaucoma) subjects can reduce their risk of developing glaucoma by supplementing with black currants.Researchers at the Sapporo Medical University School of Medicine in Japan did some wide reaching research in the direct effects of black currant supplements on glaucoma patients and those with other vision problems. The comparison was made after subjects were given 50 mg of black currant anthocyanins per day. There were 12 healthy subjects that were observed over a four week period and 38 patients with open-angle glaucoma were observed over a 24-month period. The results had two significant findings:

1) The visual field mean deviation from baseline did not change in the group taking black currant anthocyanins while the placebo group had significant visual field mean deviation

2) The ocular blood flow in the placebo group did not change in any amount, but did increase significantly in the group taking black currant anthocyanins.

A second study at the same university looked specifically at intraocular pressure and the effect of the same amount of black currant anthocyanins on subjects’ field of vision and intraocular pressure. The findings were that both healthy subjects and glaucoma patients experienced a decrease in intraocular pressure over the four week period of research. There was also evidence that the visual field deterioration was noticeably less in glaucoma patients who had consumed black currants anthocyanins.

In another study by Japanese researchers, the research looked specifically at the effect of black currant supplements on healthy eyes that did not suffer from glaucoma. The subjects in the trial were given a maximum of one tablespoon of black currant berries on a daily basis. The results showed that there was a significant amount of improved eye function and recovery from fatigue. Subject’s eyes were able to adjust faster and more effectively to dark (dark adaptation). Subjects also had greatly reduced visual fatigue after prolonged exposure to a computer screen within two hours after consumption of black currant supplements.

Research has long supported the claim that diets supplemented with anthocyanins boost the body’s immunity and ability to fight infection. Glaucoma is the number one cause of blindness in the United States. The convincing research done by Japanese scientist’s shows that successful alternative treatments for existing glaucoma may be found in the supplementation of black currant anthocyanins and these same supplements may reduce the risk of glaucoma in healthy subjects. Black currants are exceptionally high in beneficial anthocyanins and are an excellent and tasty supplement to any diet.

Black Currants– What are they?
The black currant is a woody shrub that produces a small, glossy black fruit during the summer. It can be eaten raw, but is often cooked into baked goods, made into jams and jellies and used in dietary supplements. It is grown and harvested both commercially and domestically and is a popular health supplement.

One of the greatest health attributes for the black currant is its high levels of anthocyanins. Anthocyanin pigments give fruits, vegetables, grains and flowers their dark colors like red, purple and blue. A great deal of research has been done on anthocyanins because of their roles as pollination attractants and phytoprotective agents. It is well documented that anthocyanins have health benefits as dietary antioxidants and over 300 structurally different anthocyanins have been identified in nature. There is significant evidence that these flavonoid compounds have preventative and therapeutic roles in a wide variety of human diseases because of their ability to scavenge and trap free radicals that damage biomolecules.

Glaucoma – What is it?
Glaucoma is a condition that causes damage to the optic nerve with the build-up of pressure in the eye. It gets progressively worse over time. It is often hereditary and is usually diagnosed later in life. The optic nerve’s function is to transmit images to the brain. If glaucoma is left untreated, the patient will eventually suffer from permanent and irreversable total blindness within a few years of onset.

Glaucoma is relatively easy to diagnosis, but most people with glaucoma do not report or suffer from any early symptoms that would draw their attention to the condition. Regular eye exams with an eye doctor are imperative to catch glaucoma early. Glaucoma is nicknamed the “sneak thief of vision”. You are at an increased risk of glaucoma if you: Are of African-American, Irish, Russian, Japanese, Hispanic, Inuit or Scandinavian descent
Are over age 40
Have a family history of glaucoma
Have poor vision
Have diabetes
Take certain steroid medications, such as prednisone
Have had trauma to the eye or eyes

There are two main types of glaucoma. Open-angle glaucoma or wide-angle glaucoma when the eye fluid, aqueous humor, does not flow properly through the drain in the eye even though the eye structure appears normal. Angle-closure glaucoma is caused when the poor drainage of the aqueous humor is caused by a too small angle between the iris and cornea and this narrow portion is physically blocking the draining.

Current treatments of glaucoma focus on reducing the pressure inside the eye because it is the only modifiable risk factor. There are currently three main treatment methods for glaucoma. 1) eye drops that increase the outflow of the eye fluid or reduce the amount of fluid that is formed; 2) laser surgery to eliminate the anatomical blockage of angle-closure glaucoma or increase the outflow of the eye fluid of open-angle glaucoma and; 3) microsurgery where a new channel is created to drain the eye fluid and reduce the pressure


Scientific Literature
1. Nakaishi, H., Matsumoto, H., Tominaga, S., Hirayama, M. Effects of blackcurrant anythocyanoside intake on dark adaptation and VDT work induced transient refractive alteration in healthy humans. ALTERNATIVE MEDICINE REVIEW 2000, 5; 553-562
2. Ikuyo Ohguru, Hiroshi Ohguro, Misuru Nakazawa Effects of anthocyanins in black currant on retinal blood flow circulation of patients with normal tension glaucoma. A pilot study. HIROSAKI MEDICAL JOURNAL. 59: 23-32. 2007
3. Hiroshi Ohguru, Ikuyo Ohguru, Maki Katai, Sachie Tanaka Two-year Randomized, Placebo Controlled Study of Blackcurrant Anthocyanins on Visual Field in Glaucoma. OPTHALMOLOGICA 2012, 228: 26-35
4. Hiroshi Ohguru, Ikuyo Ohguru, Saeko Yagi Effects of Blackcurrant Anthocyanins on Intraocular Pressure in Healthy Volunteers and Patients with Glaucoma. JOURNAL OF OCULAR PHARMACOLOGY AND THERAPEUTICS 2013, Vol 29 No. 1: 61-67
5. Kaori Yoshida, Ikuyo Ohguro, Hiroshi Ohguru. Blackcurrant Anthocyanins Normalized Abnormal Levels of Serum Concentrations of Endothelin – 1 in Patients with Glaucoma. JOURNAL OF OCULAR PHARMACOLOGY AND THERAPEUTICS 2013, Vol 29, No 5: 480-487