In Praise of Avocados
The Hass avocado (Persea americana Mill.) is an American success story. A California mailman named Rudolph Hass discovered this cultivar, which turns purplish-black upon ripening, and patented the tree in 1935. Every Hass avocado tree in existence is derived from a single tree that Hass planted in La Habra Heights. While Hass avocados today constitute a billion-dollar business, Hass himself made only $5,000 from his patent.
Hass avocados are often shunned by the health-conscious because of their high fat content. But most of the fat in question is monounsaturated, and thus is similar to olive oil. Other than their potential for adding poundage, avocados are a great source of nutrients, such as potassium and fiber. They have an abundance of vitamin C, vitamin E, vitamin K, folic acid, and so on. Hass avocados contain the highest lutein content of all commonly eaten fruits, as well as other carotenoids such as zeaxanthin, alpha-carotene, and beta-carotene.
In the past few years, there has been a steady stream of research on the anticancer potential of avocados. Scientists at Ohio State University (OSU) found that an extract of Hass avocado selectively induced apoptosis in cancer but not normal human oral epithelial cell lines. Apoptosis is the most common form of programmed cell death (PCD) and is the way that most drugs actually kill cancer cells.
OSU scientists believe that consuming avocados may help prevent oral cancer (Ding 2009). "As far as we know, this is the first study of avocados and oral cancer," said Dr. Steven M. Ambrosio of Ohio State. "We think these phytochemicals either stop the growth of precancerous cells in the body or they kill the precancerous cells without affecting normal cells. Our study focuses on oral cancer, but the findings might have implications for other types of cancer" (Science News 2007).
Another promising study from the University of California, Los Angeles (UCLA), showed that an extract of avocado inhibited the growth of both androgen-dependent and androgen-independent prostate cancer cell lines in the laboratory. This caught the attention of many patients, since there are few treatments that will work on prostate cancer that is no longer responding to hormone therapy. The mechanism of action was an arrest of the cell cycle accompanied by increased expression of the p27 protein. P27 helps regulate the normal cell cycle.
Many colorful fruits and vegetables also contain carotenoids. But UCLA scientists speculate that it is precisely because of the high monounsaturated fat content that the carotenoids in avocado are absorbed into the bloodstream, "where in combination with other diet-derived phytochemicals they may contribute to the significant cancer risk reduction associated with a diet of fruits and vegetables" (Lu 2005).
So, yes, avocados can be fattening; but the monounsaturated oil in this case may be serving a very good purpose. Depending on your weight, adding avocados to the diet could be an excellent idea.
In addition, avocados are considered to be among the foods that have the least amount of pesticide residues. They therefore made the "Clean 15" list of the Environmental Working Group. Fewer than 10% of avocado samples had detectable pesticides, and fewer than 1% had more than one pesticide residue (Minton 2009).
Remembering Dieter Hager
Remarks delivered at a memorial service in Bad Bergzabern, Germany, on Jan. 15, 2010.
I have come here today to both mourn and to celebrate a man that I knew as a scientist and a friend. Erich Dieter Hager was a foundational figure in the field of complementary and alternative medicine (CAM). He had an outstanding education. In the 1970s, he studied physics at the University of Stuttgart and biology at the Max-Planck-Institute for Molecular Genetics in Berlin. These studies gave him a solid grounding for his later approach to cancer, particularly the scientific application of hyperthermia.
In 1980 he received his medical degree from the University of Göttingen, one of the best universities in Germany. During this period, he also studied at England's famous Oxford University. In 1994, he went back to school and received a naturopathic medical degree as well.
In the 1980s, Dieter became medical and scientific director of Cytobiological Laboratories, Heidelberg, where he directed research in peptides, tissue engineering, and cell therapy. His first foray into complementary medicine came in 1987–1988, when he became chief physician at a cancer rehabilitation hospital, the Klinik Friedenweiler, in the Black Forest. I once accompanied Dieter on a visit to the Friedenweiler clinic, where we toured the facilities. To be honest, all I remember from that visit was Dieter taking the hairpin turns of the Black Forest roads with breathtaking speed!
In 1989, Dieter became executive medical director of the BioMed-Klinik, Hospital for Integrative Cancer Therapy here in Bad Bergzabern. It was a great pleasure to celebrate the 20th anniversary of the clinic with many of you last September. Dieter was originally from Karlsrühe, but Bad Bergzabern became his true hometown and he was very proud of its beauty and gracious ambiance. He often said that it had the finest climate in all of Germany. He also loved its wines, and after each scientific meeting here would schedule a banquet in one of the wineries. These were always joyous events, attracting attendees from all over Germany and other countries as well.
In 2004, Dieter became an adjunct professor at the University of Applied Sciences in Esslingen. There was no doubt that, had he chosen to pursue a more conventional path, he could have become a leading academic oncologist. But he always felt that the boundaries of conventional oncology were too restricting, and he saw his role as expanding the options available to cancer patients.
Complementary medicine is no less subject to divisions and infighting than any other field. But Dieter was universally respected as a leader in the field. I can truly say that I never heard one negative word spoken about him personally by anyone in the field.
In 1981, Dieter helped found the German Society of Oncology (the "DGO"), of which since 1998 I have been an honorary member. In 1982 he cofounded the Society for Biological Cancer Therapy, of which our good friend Györgi Irmey is chairman. In 1987, he also became editor of the Deutsche Zeitschrift für Onkologie (the German Cancer Journal).
Dieter was involved in many aspects of integrative medicine. You could always count on him to give any new idea a serious and respectful hearing. But, as a physicist, hyperthermia was close to his heart. Indeed, no one did more to establish the use of hyperthermia as a scientific treatment than Dieter Hager. For 18 years he served as a president or official of the International Clinical Hyperthermia Society (ICHS) and was also a founding member and officer of the German Society for Hyperthermia. All of this took enormous amounts of time, effort, and patience.
Dieter wrote many articles that are easily accessed in the international databases. But he also delivered many scientific papers in German that did not make it into the PubMed database. I want to briefly mention some of the most prominent of these:
- an October 1995 article in the German Journal of Oncology, coauthored with Ralf Kleef, MD, and others, on the complementary therapy of incurable pancreatic cancer;
- a study of quality-of-life issues in the aftercare of cancer patients, which was presented at the 5th conference on documentation and quality-of-life management in Giessen in 1997;
- a paper at the 23rd meeting of the International Clinical Hyperthermia Society in Lyon, France, June 2000, in which he demonstrated increased longevity in colon, lung; and pancreas cancer patients;
- a paper at the Selenium and Prevention conference 2000 on "Prevention, Recurrence Prophylaxis and Additive Therapies for Cancerous Diseases Through Selenium Supplementation";
- a 2002 paper on survival and quality of life in patients with advanced pancreatic cancer;
- another 2002 paper at a conference on cost-benefit ratios in medicine;
- a paper for a 2004 conference on liver metastases from colon cancer presenting the BioMed treatment for this condition;
- a 2006 paper on the therapy of metastatic melanoma, using hyperthermia, tamoxifen, interferon-alpha and complementary medicine;
- a 2008 paper on remission from myelodysplasia syndrome presented at the bone marrow aplasia (Knochenmarksaplasie) conference.
Dieter was one of the first German CAM doctors to participate in meetings of the American Society for Clinical Oncology (ASCO). With his Biomed colleagues, he made important contributions to ASCO meetings from 2000 to 2008, when he was already quite ill.
It was our yearly ritual to get together at these meetings. I enjoyed these times very much, as I had the chance to explore New Orleans, Atlanta, Chicago, and other cities with him, seeing my own country anew through his eyes.
Some of Dieter's most important contributions were made at these ASCO meetings, where he was able to reach an international audience. For instance, in 2008 he presented a paper on the use of capacitive coupled low radiofrequency (LRF) hyperthermia in the treatment of high-grade gliomas (J Clin Oncol. 2008 May 20;26 suppl; abstr 2047). Dieter and his close colleague, Friedrich Migeod, MD, presented this work to great acclaim at the Cancer Guides meeting in Washington, DC, this past June.
Dieter's pioneered the use of lithium carbonate in treating the blood deficiencies that arise from the use of chemotherapy (Hager 2001a, Hager 2002) and the use of intraperitoneal heated chemotherapy infusions in the treatment of ovarian and other peritoneal cancer (Hager 2001b). He also showed that deep hyperthermia could be used for patients with liver metastases from colorectal cancer (Hager 1999).
Dieter's care as a physician and dedication to science were exemplary. Just weeks before his death, he made a presentation at the German Society of Oncology meeting, where he received a five-minute standing ovation.
My best times with Dieter occurred during the off-hours of the ASCO meetings. I will always remember wandering the French Quarter of New Orleans with him, in June 2004, looking for a restaurant, when suddenly the skies opened up and we ran for our lives. We were totally drenched when we made it back to the hotel. Perhaps this was a metaphor: Dieter could have fun even in difficult situations. He was a realist, who took life as it came, but was also adventurous. He also walked with dignity even when there was "inclement weather" in his life.
I will miss Dieter both as a dear friend and as a treasured colleague. I trust that others, at Biomed Klinik and elsewhere, will continue to provide the treatments that he innovated. But that will not replace the wonderful personality and spirit that was Dieter Hager. To quote Shakespeare,
He was a man, take him for all in all,
I shall not look upon his like again.
– Ralph W. Moss, PhD
Avocados may help prevent oral cancer, study shows. ScienceDaily. Sep. 5, 2007.
Baronzio G, Hager D. Hyperthermia In Cancer Treatment: A Primer. Springer-Verlag; 2006.
Ding H, Han C, Guo D, et al. Selective induction of apoptosis of human oral cancer cell lines by avocado extracts via a ROS-mediated mechanism. Nutr Cancer. 2009;61:348–356.
Hager ED. Komplementäre Onkologie Adjuvante, Additive, Supportive, Therapiekonzepte für Klinik und Praxis. Forum-Med Verlagsgesellschaft. 1997.
Hager ED, Dziambor H, Höhmann D, et al. Deep hyperthermia with radiofrequencies in patients with liver metastases from colorectal cancer. Anticancer Res. 1999;19:3403–3408.
Hager ED, Dziambor H, Höhmann D, Winkler P, Strama H. Effects of lithium on thrombopoiesis in patients with low platelet cell counts following chemotherapy or radiotherapy. Biol Trace Elem Res. 2001;83:139–148 (Hager 2001a).
Hager ED, Dziambor H, Höhmann D, Mühe N, Strama H. Intraperitoneal hyperthermic perfusion chemotherapy of patients with chemotherapy-resistant peritoneal disseminated ovarian cancer. Int J Gynecol Cancer. 2001;11 Suppl 1:57–63 (Hager 2001b).
Hager ED, Dziambor H, Winkler P, Höhmann D, Macholdt K. Effects of lithium carbonate on hematopoietic cells in patients with persistent neutropenia following chemotherapy or radiotherapy. J Trace Elem Med Biol. 2002;16(2):91–97.
Hager ED et al. Intraperitoneal hyperthermic perfusion chem. of patients with peritoneal disseminated drug resistant ovarian cancer. ASCO 2008.
Lu Q, Arteaga JR, Zhang Q, et al. Inhibition of prostate cancer cell growth by an avocado extract: role of lipid-soluble bioactive substances. J. Nutr. Biochem. 2005;16:23–30.
Minton BL. Research reveals which conventional produce can be safely eaten. Naturalnews.com, June 23, 2009.
© 2010 by Ralph W. Moss, PhD
Ralph W. Moss, PhD, is the author of 12 books on cancer-related topics. The former science writer at Memorial Sloan-Kettering Cancer Center, for 35 years Moss has investigated the validity of many cancer treatments. He currently directs the Moss Reports, a library of reports for patients on over 200 different cancer diagnoses.