After the Fukushima nuclear disaster I was asked by many patients and colleagues if there are herbs that can protect against the damaging effects of ionizing radiation. While this is a valid concern, most people are unaware that we are regularly exposed to high energy radiation in a number of ways other than nuclear accidents. A significant exposure is from background radiation, due to radioactive elements in the earth and cosmic rays from space. According to the US EPA, about 8% of our annual radiation exposure comes from outer space, depending on the altitude where we live. If you’ve ever flown on a commercial airplane for four to five hours you received between 2 and 5 millirems of radiation (typical background exposure is around 360 millirems). If you’re doing a lot of flying, you can substantially increase your radiation exposure compared to background levels.
Another major source of ionizing radiation comes from medical techniques. Computed tomography (CT) scanners are now routinely used in medical practice exposing patients to a substantial increase in radiation compared to normal X-rays. For example, a chest CT scan typically delivers more than 100 times the radiation dose of a routine front and lateral chest X-ray.1 A multiphase abdomen and pelvis CT scan can deliver a radiation dose of 3,100 millirems, almost 10 times the annual background exposure.1 Recently, The Institute of Medicine concluded that the two environmental factors most strongly associated with breast cancer were ionizing radiation and postmenopausal hormone therapy,2 and an editorial in American Family Physician called for a reduction in the number of CT scans ordered, “…which are clearly being used more often than is clinically necessary.”3
The radio-protective activity of herbs is an active area of research, with most studies conducted using animal models. Such research can only be regarded as preliminary in nature; hence the focus in this article will be on human studies. Here we have two very promising leads: the standardised extract of Ginkgo biloba and the phytochemical berberine.
Ginkgo offers natural protection against radiation
According to legend, several ginkgo trees growing within one mile of the Hiroshima atomic bomb blast were among the few living things to survive and are flourishing to this day (see Wikipedia). Perhaps radiation survival is an in-built property of the ginkgo tree, since the species is a living fossil dating back more than 200 million years to a time when background radiation exposure on earth was substantially higher. Whatever the case, clinical studies do support its radio-protective activity
Ginkgo neutralized genetic damage after Chernobyl
Ginkgo neutralized genetic damage induced by radioiodine treatment in Graves’ disease patients (120mg/day; randomised controlled trial) and in Chernobyl accident recovery workers (120mg/ day; uncontrolled trial).4 The former trial assessed the effect of standardised ginkgo extract on the appearance of micronuclei (MN) in lymphocytes from patients with Graves’ disease after radioactive iodine therapy.5 Twenty-five patients were randomly assigned to receive ginkgo extract (120mg/ day) or a placebo from three days before and up to 30 days after iodine therapy. The peak increase of MN and the average increase of MN were significantly higher in the placebo group than in ginkgo treated patients. An early and sustained MN increase was seen in the placebo group, but in ginkgo treated patients the increase never reached statistical significance. The protective effect of ginkgo extract was still present after correcting the data for age, gender, thyroid hormone profile and bone marrow dose. Ginkgo didn’t have any adverse effect on the effectiveness of the radiotherapy.
A follow-up study also confirmed the radio-protective activity in radioiodine therapy. A double-blind trial evaluated the effect of ginkgo on the appearance of clastogenic factors (CFs), which have chromosome-damaging properties, in the plasma, and micronuclei in lymphocytes of patients with thyroid cancer after receiving their first dose of radioactive iodine. Twenty-three patients were randomised to receive standardised ginkgo extract (120mg/day) or a placebo from three days before and up to 30 days after radioiodine treatment.6
MN in blood lymphocytes increased significantly after radioiodine treatment in the placebo group, peaking at the 7th day and slowly declining thereafter. In patients treated with ginkgo there were no significant increases in peripheral blood lymphocyte MN at any time after radioiodine treatment.
Only the placebo group showed a significant, progressive increase in CFs. This peaked at the 14th day with a slight decrease thereafter but never returned to baseline values. In contrast, in ginkgo-treated patients the activity of CFs was negligible at each time point. The differences in the change in lymphocyte MN and CFs activity between the placebo and ginkgo-treated groups were significant (p < 0.01 and p < 0.05, respectively). After radioiodine treatment, thyroid function tests were similar in both groups. No clinically-relevant side effects were observed from ginkgo treatment.
Berberine’s radio-protective abilities confirmed in studies
The phytochemical berberine has radio-protective activity, according to clinical trials. Given the traditional role of berberine-containing herbs in China for the treatment of diarrhoea, the impact of berberine on radiation-induced acute intestinal syndrome (RIAIS) was explored in a clinical study.7 RIAIS includes side effects such as nausea, vomiting, abdominal pain, loss of appetite, diarrhoea, colitis and proctitis. Thirty six patients with seminoma (a type of testicular cancer) or lymphoma, and another 42 with cervical cancer, were randomly administered either berberine (900mg/day) or a placebo for four and five weeks, respectively. The berberine was given just prior to and during abdominal or pelvic radiotherapy. Berberine significantly improved the incidence and severity of RIAIS in both patient groups by the end of the trial (p<0.05), and also reduced existing RIAIS in a separate group of eight patients. The treatment was well tolerated.
In a prior randomized, double-blind, placebo-controlled study, the effect of six weeks of berberine (20mg/kg/day) on radiation-induced lung injury (RILI) was assessed in 90 patients undergoing treatment for non-small cell lung cancer.8 The incidence of RILI was significantly lower in the berberine group compared with the placebo group at six weeks and at a six-month follow-up (45.2% vs 72.1% and 35.7% vs 65.1%, respectively, both p<0.05). Two measures of radiation-induced lung tissue damage (soluble intercellular adhesion molecule-1 and transforming growth factor beta 1) were also significantly reduced at six weeks compared with the placebo (p<0.01 for both) and two measures of lung function were significantly improved at six months.
We can take some positive action with these supplements to minimize radiation damage, and the studies show that they certainly do no harm. Next time you’re taking a long flight or having a CT scan, think of ginkgo and berberine. If possible, it’s best to start about one week before the exposure and continue for a week after. With radiation therapy for cancer, I recommend that ginkgo not be taken in a 24-hour window on either side of treatments to avoid any risk of interference. Be sure to talk to your doctor about the best approach for you.
To your better health,
Nutrition & Healing
Volume 7, Issue 9 – September 2013
Full references and citations for this article are available in the downloadable PDF version of the monthly Nutrition and Healing issue in which this article appears.