Eat Your Broccoli

Do you remember when your mom said ‘Eat your broccoli!’? Do you remember how annoying that was? Well, she was right! And the reason is sulforaphane. Sulforaphane in broccoli can greatly reduce your cancer risk, detoxify your system, and even work towards reducing Alzheimer’s.

Sulforaphane protects against depression, cancer and Alzheimer's

It all comes down to the fact that inflammation eventually kills you and sulforaphane can help fight inflammation. No matter how healthy you try to live, you will have inflammation going on somewhere in your body—whether it’s a reaction to pollutants you breathed in, from sunlight, as a reaction to diet and even exercise, or simply aging—there is no way to escape inflammation. Mostly, our bodies do quite a good job of keeping everything under control but given the high exposure to the toxins of a modern world, it makes sense to support our bodies in fighting inflammation. Precisely that’s what sulforaphane does—and very effectively.

I discovered that not only broccoli, but all so-called cruciferous vegetables contain sulforaphane in varying amounts. What are cruciferous vegetables, you might ask? The word ‘cruciferous’ is derived from the petals having a cross-like shape. Think broccoli, brussels sprouts, garden cress, mustard greens, turnips, cabbage, kale, watercress, kohlrabi, broccoli, radish, cauliflower, rocket, and bok choy (yummy!). The most effective way to get lots of sulforaphane into your body is by eating broccoli sprouts. I’ll go into details later.

Cruciferous vegetables

Lowering inflammation & detoxification

Consuming sulforaphane regularly causes a reduction in blood inflammation markers, LDL and blood glucose.1 2 Furthermore, it enhances the excretion of harmful compounds we are all exposed to on a daily basis.

Sulforaphane can aid in detoxification of airborne pollutants. Just 24 hours after consuming a broccoli sprout smoothie, people washed out 61% more of harmful benzenes, which are found in airborne pollutants and cigarettes.3 Benzene is a carcinogen of which smokers consume up to 2 mg of daily. Compare that to non-smokers who consume only 0.2 mg probably from air pollution and secondhand smoke.4 Eating just 4.5 servings of raw cruciferous vegetables per month reduced the lung cancer risk of smokers by 42%, and there was an even stronger association for those who smoked for less than 30 years.5 Amazing right? So if you smoke, the best thing to do is quit. But if that is not an option, definitely make sure you are getting enough sulforaphane into your system.

Cancer prevention

Evidence has found sulforaphane to be a powerful agent in cancer prevention. Three to five servings of cruciferous vegetables per week decreased men’s risk of prostate cancer by 41%.6 Supplementing patients who had been operated for prostate cancer with 60 mg of sulforaphane caused a slowing down of the doubling rate of the prostate cancer tumor marker by 86%.7 Men who ate more than five servings of cruciferous vegetables had a 51% decrease in their bladder cancer risk.8

In healthy women, sulforaphane accumulates in the breast tissue where it may act preventatively against breast cancer. From animal studies we know that sulforaphane can turn on an important gene involved in detoxification within breast tissue.9 There are quite a few studies showing that women who consume cruciferous vegetables at least once a week had between a 17-50% decrease in breast cancer risk.10 This huge variation is probably due to the fact that (1) the bioavailability of sulforaphane is extremely varied in cruciferous vegetables and (2) it greatly depends on how you eat them; we’ll talk more about this in the next blog post.

Reducing neurodegenerative disease

Some areas of your body are especially sensitive to inflammation. One of them is your brain. Neurodegenerative disease such as Alzheimer’s, Parkinson’s and Huntington’s disease have all been linked to brain inflammation. Researchers have shown that sulforaphane can cross the blood-brain barrier in mice11, so we expect this to be similar in humans, which means it can also have an impact on processes in the brain.

Sulforaphane for neurodegenerative disease such as Alzheimer's, Parkinson's or Huntington's disease

Mice induced with neurodegenerative diseases have shown improvements in pathologies after sulforaphane injections. Sulforaphane has also shown the ability to enhance neurite outgrowth, which is a way neurons repair themselves after injury such as a traumatic brain injury. Additionally, results from this study showed that juvenile and adolescent mice fed with a sulforaphane-enriched diet had less stress-induced depression-like behaviors as adults.12

This is super exciting, as it shows that sulforaphane taken in adolescence, may act as a prophylactic for depression and may enhance stress resistance. So parents, although this has only been shown in animals, it definitely can’t harm to feed your kids cruciferous vegetables on a regular basis.

Decreasing depression

Nutrition has a huge impact on depression by affecting not only synthesis of neurotransmitters but also inflammation levels in your body. Why is that? Remember that inflammation harms your body, thus your immune system produces little cells that fight the inflammation. Unfortunately, these cells are built from the same amino acid that your brain uses to produce serotonin; it’s called tryptophan. Now, if you have constant inflammation going on in your body, there might not be enough tryptophan left for the brain to synthesize sufficient levels of serotonin which, in turn, can cause depression.13

In studies involving mice, researchers induced depression by inflammation and then showed they could reverse it by giving the mice sulforaphane. They even went as far as showing that sulforaphane can decrease depressive symptoms with the same efficacy as Prozac.14 This has only been shown in animals but because we know sulforaphane decreases inflammation in humans and we know inflammation can cause depression, it’s reasonable to hypothesize that sulforaphane may decrease symptoms of depression.

Positive effects on autism

Young men with moderate to severe Autistic Spectrum Disorder (ASD), have also shown improvement when consuming sulforaphane daily for 18 weeks. Improvements were seen in social interaction, aberrant behavior and verbal communication.15

Protection from sunburn

Even our largest organ – our skin – is affected by sulforaphane. Topically applied, three-day old broccoli sprout extract protected human skin from sunburn.16 So maybe we will soon be finding broccoli sprout extract in our sunscreens and after sun products? It certainly wouldn’t surprise me.

Sulforaphane as UV sun protection

What’s the take-home message?

To sum up, there is plenty of evidence showing links between the consumption of sulforaphane, found in cruciferous vegetables, and the reduction of certain cancers and cardiovascular risks, as well as improvements in neurodegenerative disease and in detoxification of airborne pollutants.

Currently, there are 12 clinical trials investigating the effects of sulforaphane, four looking into links with autism, three looking into it as a cancer treatment, and the rest looking into all sorts of possible treatments from allergic rhinitis to schizophrenia. This means we will get new insights very soon.

Our next two posts on sulforaphane will deal with

  1. How it works in your body, and
  2. What you can do to maximize your dietary intake. Because simply eating broccoli soup every day won’t do the trick.

Stay tuned. You can also sign up for our mailing list and get notified when we publish part two and three of this series.

 


References

  1. Bahadoran Z, Mirmiran P, Hosseinpanah F, et al. Broccoli sprouts powder could improve serum triglyceride and oxidized LDL/LDL-cholesterol ratio in type 2 diabetic patients: a randomized double-blind placebo-controlled clinical trial. Diabetes Res Clin Pract. 2012 Jun;96(3):348-54. doi: 10.1016/j.diabres.2012.01.009. Epub 2012 Feb 9. PubMed PMID: 22325157 

  2. Axelsson AS, Tubbs E, Mecham B, et al. Sulforaphane reduces hepatic glucose production and improves glucose control in patients with type 2 diabetes. Sci Transl Med. 2017 Jun 14;9(394). pii: eaah4477. doi: 10.1126/scitranslmed.aah4477. PubMed PMID: 28615356. 

  3. Egner PA, Chen JG, Zarth AT, et al. Rapid and sustainable detoxication of airborne pollutants by broccoli sprout beverage: results of a randomized clinical trial in China. Cancer Prev Res (Phila). 2014 Aug;7(8):813-23. doi: 10.1158/1940-6207.CAPR-14-0103. Epub 2014 Jun 9. PubMed PMID: 24913818 

  4. Wallace L, Pellizzari E, Hartwell TD, et al. Exposures to benzene and other volatile compounds from active and passive smoking. Arch Environ Health. 1987 Sep-Oct;42(5):272-9. PubMed PMID: 3452294 

  5. Tang L, Zirpoli GR, Jayaprakash V, et al. Cruciferous vegetable intake is inversely associated with lung cancer risk among smokers: a case-control study. BMC Cancer. 2010 Apr 27;10:162. doi: 10.1186/1471-2407-10-162. PubMed PMID: 20423504. 

  6. Cohen JH, Kristal AR, Stanford JL. Fruit and vegetable intakes and prostate cancer risk. J Natl Cancer Inst. 2000 Jan 5;92(1):61-8. PubMed PMID: 10620635. 

  7. Cipolla BG, Mandron E, Lefort JM, et al. Effect of Sulforaphane in Men with Biochemical Recurrence after Radical Prostatectomy. Cancer Prev Res (Phila). 2015 Aug;8(8):712-9. doi: 10.1158/1940-6207.CAPR-14-0459. Epub 2015 May 12. PubMed PMID: 25968598. 

  8. Michaud DS, Spiegelman D, Clinton SK, et al. Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort. J Natl Cancer Inst. 1999 Apr 7;91(7):605-13. PubMed PMID: 10203279 

  9. Cornblatt BS, Ye L, Dinkova-Kostova AT, Erb M, et al. Preclinical and clinical evaluation of sulforaphane for chemoprevention in the breast. Carcinogenesis. 2007 Jul;28(7):1485-90. Epub 2007 Mar 7. PubMed PMID: 17347138 

  10. Terry P, Wolk A, Persson I, Magnusson C. Brassica vegetables and breast cancer risk. JAMA. 2001 Jun 20;285(23):2975-7. PubMed PMID: 11410091; Wu YC, Zheng D, Sun JJ, et al. Meta-analysis of studies on breast cancer risk and diet in Chinese women. Int J Clin Exp Med. 2015 Jan 15;8(1):73-85. eCollection 2015. PubMed PMID: 25784976 

  11. Jazwa A, Rojo AI, Innamorato NG, et al. Pharmacological targeting of the transcription factor Nrf2 at the basal ganglia provides disease modifying therapy for experimental parkinsonism. Antioxid Redox Signal. 2011 Jun 15;14(12):2347-60. doi: 10.1089/ars.2010.3731. Epub 2011 Mar 28. PubMed PMID: 21254817 

  12. Yao W, Zhang JC, Ishima T, et al. Role of Keap1-Nrf2 signaling in depression and dietary intake of glucoraphanin confers stress resilience in mice. Sci Rep. 2016 Jul 29;6:30659. doi: 10.1038/srep30659. PubMed PMID: 27470577 

  13. Rhonda Patrick on Joe Rogan: #901: http://podcastnotes.org/2017/02/13/jre-901-rhonda-patrick-is-back/ 

  14. Martín-de-Saavedra MD, Budni J, Cunha MP, et al. Nrf2 participates in depressive disorders through an anti-inflammatory mechanism. Psychoneuroendocrinology. 2013 Oct;38(10):2010-22. doi:10.1016/j.psyneuen.2013.03.020. Epub 2013 Apr 23. PubMed PMID: 23623252 

  15. Singh K, Connors SL, Macklin EA, et al. Sulforaphane treatment of autism spectrum disorder (ASD). Proc Natl Acad Sci U S A. 2014 Oct 28;111(43):15550-5. doi: 10.1073/pnas.1416940111. Epub 2014 Oct 13. PubMed PMID: 25313065 

  16. Knatko EV, Ibbotson SH, Zhang Y, et al. Nrf2 Activation Protects against Solar-Simulated Ultraviolet Radiation in Mice and Humans. Cancer Prev Res (Phila). 2015 Jun;8(6):475-86. doi: 10.1158/1940 6207.CAPR-14-0362. Epub 2015 Mar 24. PubMed PMID: 25804610 

Deodorants Don't Cause Breast Cancer

Many people believe that antiperspirants cause breast cancer, especially if applied after shaving. Here is why you can happily use your antiperspirant and why you might want to throw it out anyway.

does aluminum cause cancer

I have tried very hard to stay away from antiperspirants for the last few years because someone told me that the aluminum in them causes breast cancer. Back then, I googled this claim and found plenty of posts agreeing with this statement and thus believed it. It was pretty difficult to make the switch from antiperspirants to deodorants at the beginning, but I’ve simply gotten used to it 5 years down the line, although for eventful/stressful occasions I still bring out my very effective bottle of antiperspirant. I decided it was time to investigate sweating, deodorants and antiperspirants and whether there was any truth to this lifestyle change. Turns out, there isn’t much. But there’s a lot we should all be aware of.

Why we sweat at all
How deodorants and antiperspirants work
Can aluminum in antiperspirants cause cancer?
Brand-new approach to odors

Why we sweat at all

The skin is our largest organ and apart from its main role as the first line of defense in the immune response system, it regulates the body’s temperature.

Perspiration is the main way to make sure the body’s temperature stays below 40°C (104°F). Above this temperature proteins become denatured (meaning they lose their structure) leading to cell death and eventually organ failure. Our body’s temperature can be increased by many different things such as high environmental temperatures, movement or metabolic energy, emotional stress, and even by spicy food.

When sweat is released, the thermal energy is released by evaporation on the skin’s surface. Interestingly, sweating varies depending on its trigger. Thermoregulatory sweating occurs all over the body and happens in response to heat stress. Emotional sweating, on the other hand, can happen over the whole body, but tends to affect mostly the palms, soles and armpits. This kind of sweating is thought to be an evolutionary trait to prevent slipping while running or climbing in stressful situations, as it increases friction.1 Yes, moist hands have a better grip. Maybe you know the feeling of trying to open a plastic bag at the supermarket with dry hands and no success? All you have to do is wet your fingers a little bit. Same principle.

Sweating is not only very important to maintain our health, it is also one of the main reasons we look and think the way we do. The Homo sapiens sapiens, in comparison to other primates, has less body hair and the ability to produce up to 12 liters of sweat per day. We can proudly say, we are the sweatiest primates. Nina Jablonski, an anthropologist, believes that the reason we lost our body hair was that it allowed us to cool off faster, thereby giving us a distinct advantage over other primates. We can run over greater distances and hunt bigger game. Some speculate, that sweating has also been a factor in the development of larger brains.2 The function of large brains produces a lot of heat, which can only be maintained by an effective cooling system.

The downside of all this healthy sweating is that it does tend to make us smelly. It allows a whole lot of different commensal bacteria (called microbiota) to form in places with lots of sweat glands such as the armpit. The armpit is dominated by the following bacteria: Staphylococcus, Corynebacterium (considered to be the primary odor-causing bacteria), Betaproteobacteria, Clostridiales, Lactobacillus, Propionibacterium, and Streptococcus.3 These are found in the sebaceous and sweat glands, although mostly bad odor is associated with the apocrine gland, a certain kind of sweat gland.4

How deodorants and antiperspirants work

In order to control the often uncomfortable smell caused by bacteria found on our skin, the ancient Egyptians, Greeks, and Romans simply bathed often and used perfumes such as aromatic oils to cover up malodors. Up until the 19th century, Europeans used eau de cologne to mask body odors. In 1888 the first antiperspirant was made of (slightly) antibacterial zinc oxide that came in a wax-like cream form and was called MUM.5 Some other products arrived on the market in the early 20th century using aluminum chloride, such as Odorono (“Odor – Oh – No”), which had to be mixed with acid to be effective. The acidic solution irritated the skin and could damage clothing.6

Thank goodness we’ve come a long way since then. Today, there are 2 types:

  1. Deodorants – which mask, modify or prevent body odor usually by anti-microbial agents that reduce bacteria (alcohol) and
  2. Antiperspirants – deodorants with components that physically plug the underarm sweat ducts using mostly aluminum salts.

People tend to worry about using aluminum because it has been shown to be able to accumulate in most tissues, such as the brain and liver. It has been associated with neurological disease due to inducing oxidative stress in neuronal cells. The problem is that aluminum is found in so many everyday substances from your drinking water, food, drugs, and of course in most antiperspirants. It is estimated that the average dietary intake ranges from 3-30 mg per day.7

The way aluminum in antiperspirants temporarily block sweat ducts, is by precipitating inside the sweat glands and producing insoluble aluminum hydroxide which plugs the glands and thereby blocks the secretion of sweat. Scientists have shown that aluminum can be absorbed via the skin as it was found in very slight levels in the blood and urine. They calculated an average of 3.6 mg of aluminum is absorbed after a one time application, although expect this to be less under normal conditions (bandages were used to detect aluminum recovered from skin). This proves that although the underarm application of antiperspirants does not increase the burden of aluminum in the body, it can be absorbed.8

Can aluminum in antiperspirants cause cancer?

The whole idea of linking aluminum in antiperspirants to breast cancer started with an e-mail hoax back in the 1990s suggested that chemicals in antiperspirants cause breast cancer. This turned into an urban legend and spread like wildfire. To shed some light on this rumor, a study was published in 2002, which included 1,606 women (roughly half of them diagnosed with breast cancer and the other half as controls). They found no association between the use of deodorants or antiperspirants and the risk of breast cancer. They also demonstrated that applying either deodorants or antiperspirant within an hour of shaving has no influence on the risk for breast cancer.9 To sum it up, they myth-busted this rumor.

But shortly after, another study was published, which concluded that more frequent use of deodorants or antiperspirants was linked with a breast cancer diagnosis at an earlier age. This study included 437 women who had all survived breast cancer and did not include a control group.10

If an experiment lacks controls, one can find statistical causal links between arbitrary activities and breast cancer.

I could, for example, choose flossing teeth, and then go on to ask breast cancer survivors when they began flossing. The data would provide me with a statistical relationship. Regrettably, this study was interpreted by many as evidence for a connection between breast cancer and deodorant/antiperspirant use. Whereas, the only meaningful conclusions we can extract from this is that women who use deodorants tend to be younger.11

deodorant and breastcancer debunked

However, another study in 2006 in Iraq, showed that the use of deodorants reduced the risk of breast cancer. Unfortunately, I was not able to read the actual study, but a review showed that this study and the first study with 1,606 women were the only two with proper controls in place investigating this association.

We can also dismiss another study in 2005, which suggested a link between deodorant application and breast cancer due to the increased incidence of tumors in the upper, outer quadrant of the breast.12 Some suggest, that the high proportion of breast cancer in the upper, outer quadrant of the breast is because there is more tissue in that quadrant13 14 But it has never been confirmed to be the reason for more cancers originating in this particular area. We still don’t know why this is the case.

In case you are worried about using antiperspirants or deodorants during radiation therapy for breast cancer, a study of 300 women showed that there was no difference in armpit skin reactions between the two groups.15

The answer to the question if there is any scientific proof that antiperspirants or deodorants cause cancer is clearly ‘No’.

If you want to avoid breast cancer, or any kind of cancer, some of the biggest culprits are alcohol, tobacco, obesity, sunlight, radiation and infectious agents, such as the human papilloma virus which causes cervical cancer, or hepatitis B and C which can cause liver cancer, or HIV. And of course age. But you won’t manage to avoid that. There are still more and the National Institute of Health does quite a good job of describing these in detail if you are interested.

Brand-new approach to odors

All this data suggests we can happily go on using any kind of antiperspirant or deodorant. We do, however, need to be aware that we are changing the natural microbiota of our skin by doing so; this also counts for shampoo, soaps, body washes, and lotions.

A recent study looked at the influence of (1) antiperspirants (containing aluminum zirconium trichlorohydrex Gly as the active ingredient), (2) deodorants and (3) the use of no deodorants in a total of 18 participants. The antiperspirant changed the armpit microbiota, decreasing the percentage of Corynebacterium and making armpits more species rich. Since antiperspirants have only been in use for roughly a 100 years, we don’t know how these new species will interact with the function of beneficial skin symbionts. Just like the human gut microbiota, the skin microbiota could be seen as an antibiotic resistance reservoir. Changing its composition could have any kind of effects ranging from good to bad.3

Ditch your deodorant, already!

New studies suggest a move away from the extreme clean and hygienic approach of the past, towards a more natural and sustainable kind of skin care. A new start up16 came up with an innovative approach to this problem. They developed a bacterial mist made of ammonia oxidizing bacteria called Nitrosomonas, which have been eliminated from our skin’s microbiota by modern soaps and detergents. They sell their products online. In an entertaining article by Julia Scott in the New York Times you can read about her testing the products for four weeks.

It looks like we are ready for a new approach to skin care in general, including new odor-reducing products and there are quite a few innovative companies looking at this. Who knows, in another 100 years we might all be spraying bacteria onto our armpits or be wearing garments that simply don’t smell.

 


References

  1. Wilke K, Martin A, Terstegen L, Biel SS. A short history of sweat gland biology. Int J Cosmet Sci. 2007 Jun;29(3):169-79. doi:10.1111/j.1467-2494.2007.00387.x. PubMed PMID: 18489347. 

  2. https://www.scientificamerican.com/article/the-naked-truth/ 

  3. Urban J, Fergus DJ, Savage AM, Ehlers M, Menninger HL, Dunn RR, Horvath JE.The effect of habitual and experimental antiperspirant and deodorant product use on the armpit microbiome. PeerJ. 2016 Feb 2;4:e1605. doi: 10.7717/peerj.1605.PubMed PMID: 26855863; PubMed Central PMCID: PMC4741080  2

  4. James AG, Austin CJ, Cox DS, Taylor D, Calvert R. Microbiological and biochemical origins of human axillary odour. FEMS Microbiol Ecol. 2013 Mar;83(3):527-40. doi: 10.1111/1574-6941.12054. Review. PubMed PMID: 23278215 

  5. History of MUM 

  6. The history of antiperspirants in the USA from Smithsonian.com 

  7. Maya S, Prakash T, Madhu KD, Goli D. Multifaceted effects of aluminium in neurodegenerative diseases: A review. Biomed Pharmacother. 2016 Oct;83:746-754. doi: 10.1016/j.biopha.2016.07.035. Review. PubMed PMID: 27479193 

  8. Flarend R, Bin T, Elmore D, Hem SL. A preliminary study of the dermal absorption of aluminium from antiperspirants using aluminium-26. Food Chem Toxicol. 2001 Feb;39(2):163-8. PubMed PMID: 11267710 

  9. Mirick DK, Davis S, Thomas DB. Antiperspirant use and the risk of breast cancer. J Natl Cancer Inst. 2002;94:1578–1580 

  10. McGrath KG. An earlier age of breast cancer diagnosis related to more frequent use of anti- perspirants/deodorants and underarm shaving. Eur J Cancer Prev. 2003;12:479–485 

  11. Jones J. Can rumors cause cancer? J Natl Cancer Inst. 2000 Sep 20;92(18):1469-71. PubMed PMID: 10995800 

  12. Darbre PD. Recorded quadrant incidence of female breast cancer in Great Britain suggests a disproportionate increase in the upper outer quadrant of the breast. Anticancer Res. 2005 May-Jun;25(3c):2543-50. PubMed PMID: 16080490 

  13. Hardefeldt PJ, Edirimanne S, Eslick GD. Deodorant use and breast cancer risk. Epidemiology. 2013 Jan;24(1):172. doi: 10.1097/EDE.0b013e3182781684. Review. PubMed PMID: 23232621 

  14. Lee AH. Why is carcinoma of the breast more frequent in the upper outer quadrant? A case series based on needle core biopsy diagnoses. Breast. 2005 Apr;14(2):151-2. PubMed PMID: 15767185 

  15. Lewis L, Carson S, Bydder S, Athifa M, Williams AM, Bremner A. Evaluating the effects of aluminum-containing and non-aluminum containing deodorants on axillary skin toxicity during radiation therapy for breast cancer: a 3-armed randomized controlled trial. Int J Radiat Oncol Biol Phys. 2014 Nov 15;90(4):765-71. doi:10.1016/j.ijrobp.2014.06.054. PubMed PMID: 25194668 

  16. AOBiome 

What Zika is and how to avoid it

Why should we care about Zika? News of the Zika virus is all around, but how dangerous is it really? And is Zika relevant for people who are not intending to have kids? Here’s my four-part journey on what we actually know and don’t know about the Zika virus to date.

Part 1: What is Zika and why is it in the news?
Part 2: What diseases does Zika cause? How do I know if I have Zika?
Part 3: How do I avoid getting Zika?
Part 4: What’s the future of the Zika virus?

Part 1: What is Zika and why is it in the news?

Zika is not a new virus. Like all zoonotic viruses (meaning of non-human origin that’s jumped over to humans) it has been around for a long time. So why are we only hearing about it now? Perhaps because we didn’t think it was a virus that causes serious damage and the number of people affected by it was limited. In fact, there are many small virus outbreaks that no one ever hears about simply because of their magnitude. If you want to get hysterical about possible looming epidemics, check out the website of the European Centre for Disease Prevention and Control (ECDC).

Zika is a flavivirus, which means it belongs to the same group as dengue, yellow fever, Japanese encephalitis, and the West Nile virus.

Zika virus particle
Zika virus particle (By Manuel Almagro Rivas, CC BY-SA 4.0, via Wikimedia Commons)

The virus was first isolated from a sick monkey in the Zika Forest in Uganda in 1947, hence its name. It was then found in mosquitoes in that same forest a few years later. In 1968, Zika was first isolated from humans in Nigeria. It was known that the virus caused mostly transient febrile illness, in combinations with a possible rash, headache, joint pain, and conjunctivitis. Most patients recovered fully within a week and so the disease associated with the Zika virus was perceived as mild and self-limiting.

In 2007, however, there was an outbreak on Yap Island in the southwestern Pacific Ocean. This was the first time the virus was detected outside of Africa and Asia, and it had infected nearly 75% of the population.1 In 2013 Zika’s spread continued to French Polynesia, and it was estimated that around 32,000 people were infected. This time a few cases of Guillain-Barré syndrome (GBS) were linked to the virus. GBS is a disorder in which the body’s immune system attacks its own nerve cells, which can lead to paralysis.2 There is only an association between Zika and GBS – the literature on the causality between Zika and GBS is unsatisfactory.3 What we do know is that neurological problems, not necessarily GBS, can arise following Zika infections.

Zika transmission worldwide, 28 October 2016
Zika transmission worldwide, 28 October 2016 (ECDC)

After French Polynesia, more and more Pacific islands were affected by outbreaks in 2014 and 2015, but the reason you and I know about Zika is because Brazil was hit hard in 2015, and the Olympics were planned for 2016. Within a few months Brazil had 1.3 million suspected cases. By September 2015 there was an unusual increase in the number of infants born with microcephaly in the same area Zika had first been reported.4 And so the rest of the world took notice.

Part 2: What diseases does Zika cause? And how do I know if I have Zika?

In 80% of cases, after being infected by the Zika virus, you won’t notice anything. If you do, you’re most likely to come down with a mild flu. Only in very rare cases does it cause neurological problems. I asked myself just how rare, but could not find any solid information on how many patients actually get neurological problems following a Zika infection. Zika can cause severe problems for an unborn child of a Zika-infected mother called the congenital Zika syndrome, which includes microcephaly.

Microcephaly
Microcephaly (By Centers for Disease Control and Prevention via Wikimedia Commons)

Microcephaly basically means a baby’s head is much smaller than expected, usually leading to developmental delays, intellectual disability, and a range of other problems from mild to severe. Microcephaly is another possible outcome from infection with toxoplasmosis,5 rubella or cytomegalovirus during pregnancy, so it’s not exclusively linked to the Zika virus.6 A preliminary study with 42 patients showed that 29% of the Zika infected mothers showed fetal abnormalities. Of the 12 infected mothers, two had miscarriages. It also didn’t matter when during pregnancy the women were infected.7

The more I dug into the association between Zika and birth defects, the foggier the information became. It is important to remember that most pregnant Zika infected women are having babies without any abnormalities. We really don’t know yet why there is this sudden increase in cases of microcephaly in the South American population, and why this was not seen in previous years. Some hypothesize that there may be differences in Zika’s ability to cause disease.8 Zika’s ability to mutate/change very quickly is due to it being an RNA virus rather than a DNA virus.9 Others argue that the effects of Zika seem worse at the moment because a larger population is affected and the Americas provide an ideal mosquito-breeding climate.

A brand new study published in Nature on the 31st of October showed that mice testes are severely damaged by Zika. These results highlight the uncertainty surrounding Zika and the need to investigate Zika’s effects on the function and viability of sperm in humans.10

How do I know if I have Zika?

Get tested. The CDC recommends that asymptomatic women who live in areas with active Zika transmission should be tested for Zika IgM as part of the routine obstetric care during the 1st and 2nd trimesters. This test tells you if the person’s immune system has created an antibody response to a flavivirus, not necessarily Zika. If the test is positive, you could have had dengue or another flavivirus.11 Therefore, a positive IgM test should be followed by a real time RT-PCR test,12 which gives a definitive diagnosis of Zika infection. The testing is equivalent for men.

Part 3: How do I avoid getting Zika?

How to avoid getting Zika
Transmission of Zika virus and how to avoid getting Zika

Mosquito

The number one way to get infected with the Zika virus is by being bitten by a mosquito. Mostly the culprit is the Aedes mosquito species (specifically A. aegypti and A. albopictus), which typically bite during the daytime and are widely spread throughout the tropical and subtropical regions as well as most of southern Europe.4

Areas in Europe where Aedes albopictus is present, July 2016
Areas in Europe where Aedes albopictus is present, July 2016 (ECDC and EFSA, VectorNet)

 

Sexually transmitted

Researchers have been able to detect virus particles in the blood, urine and semen (as well as saliva and tears) of infected patients, and over 30 cases of sexual transmission have been documented.

When I looked into this more closely, I found lots of conflicting information on how long Zika remains in the blood, and if all the bodily fluids, in which virus particles have been detected, can actually be infectious. Unfortunately, most studies have only been able to follow patients for a short period of time, because Zika has only been in the spotlight over the past year. Zika was detected in the blood of a patient for up to 81 days after the onset of symptoms.13 This was the longest recorded case of Zika found in blood.

The WHO has recommended asymptomatic men and women returning from Zika endemic areas, to wait 6 months before having unprotected sex.14 The Zika virus seems to reside longest in semen with studies showing it was detected in one patient for up to 188 days, 181 days in another and 92 days in a third patient. In the first two case studies the final samples taken contained Zika, whereas in the third study no virus was detected in subsequent samples. Therefore, I believe that it may be wise to wait longer than 6 months. If you are family planning and have returned from a Zika-endemic country, it’s a good idea to get tested, because you could still be carrying the virus.

from mother to fetus

Virus particles were detected in the amniotic fluid, fetal brain, and in the blood of babies, as well as in the breast milk of infected mothers.

via blood transfusion

In August 2016 the FDA put forward the recommendation that all blood donations should be tested for the Zika virus, but this is an expensive recommendation.

Testing for Zika (with real time RT-PCR) can cost up to $500 per test in the USA, while a clinic in London offers this test for £383. In Austria you can get tested at the “Referenzzentrale für Arboviren an der Virologie der Medizinischen Universität Wien”.

Checklist for family-planners

  • Avoid traveling to areas with wide spread transmission. At the moment most of South America, Mexico, USA – in particular Florida, Thailand and the Philippines, for weekly updates check the website of the ECDC
  • Don’t have unprotected sex with someone recently back from one of these areas, or make sure that person has tested negative for Zika
  • Plan your next summer holidays away from the areas likely to get Zika next summer, this includes most of southern Europe – the mountains are a great alternative

Part 4: What’s the future of the Zika virus?

Research on Zika has taken off and fortunately funding has increased to meet the demands set by this new epidemic. This can be seen by the number of publications found on PubMed: since the first paper in 1952 there were a total of 208 publications until 2016. A stunning 88% of all Zika papers on PubMed15 were published in the last 11 months!

Researchers are trying to understand the virus, how it spreads, and the resulting disease in order to develop possible therapies and vaccines. Currently, there are 4 clinical trials focused on Zika vaccines registered on clinicaltrial.gov. However, the fear is that vaccinating a large population may not be cost-effective, as there are only sporadic outbreaks. This means the cost of disease treatment may be lower than the cost of a Zika vaccine. Another worry is that a vaccine will simply not be affordable to the parts of the world that need it most.16 The research community is facing questions such as which population to vaccinate and when, as well as classic vaccination problems, like how many doses are necessary to achieve protection and just how long this protective effect will last.17

Is there a way to treat Zika?

No approved anti-virals for Zika exist yet. To discover new treatments for the Zika virus, scientists have thrown together FDA-approved drugs or compounds, human cells, and the Zika virus in a Petri dish to see which drugs reduce or stop the infection. This method has generated a few possible anti-viral candidates, but these need to undergo much more testing before they can even be considered in preliminary human trials.18 19

What’s the situation in Austria?

One of the main reasons I began investigating this topic is to know what my risks are of catching Zika right here in Austria. It turns out, Zika has even made it to Austria. We have had 29 diagnosed Zika cases in 2016,20 but these were all imported from other countries. So far it seems we are safe from Zika, but this could change with warmer summers and new mosquito populations.

What can we expect in the future?

The bad news: Zika will continue to spread. The mosquito A. albopictus is already present in many parts of southern Europe (e.g. Italy, parts of France & Spain), the chances are relatively high that one of these bites an infected individual and begins spreading the virus. In Europe most pregnant women are screened at the start of pregnancy to determine their immune status on a few dangerous infections during pregnancy. I can only assume Zika will eventually be added to the list.

The good news: Zika appears to be mostly a harmless virus, with only 20% of all infected individuals actually getting any symptoms at all. So my suggestion: don’t panic.


  1. Hayes EB. Zika virus outside Africa. Emerg Infect Dis. 2009 Sep;15(9):1347-50. doi: 10.3201/eid1509.090442. Review. PubMed PMID: 19788800. 

  2. Information on GBS from the Mayo Clinic 

  3. Leis AA, Stokic DS. Zika Virus and Guillain-Barre Syndrome: Is There Sufficient Evidence for Causality? Front Neurol. 2016 Sep 30;7:170. PubMed PMID: 27746763. 

  4. Petersen LR, Jamieson DJ, Powers AM, Honein MA. Zika Virus. N Engl J Med. 2016 Apr 21;374(16):1552-63. doi: 10.1056/NEJMra1602113. Review. PubMed PMID: 27028561.  2

  5. In Austria from 1992 to 2008, 13% of women infected with toxoplasmosis during pregnancy transmitted the infection to the fetus. (Prusa AR, Kasper DC, Pollak A et al. The Austrian Toxoplasmosis Register, 1992-2008. Clin Infect Dis. 2015 Jan 15;60(2):e4-e10. doi: 10.1093/cid/ciu724. PubMed PMID: 25216688.) 

  6. The CDC’s information on microcephaly 

  7. Brasil P, Pereira JP Jr, Raja Gabaglia C et al. Zika Virus Infection in Pregnant Women in Rio de Janeiro – Preliminary Report. N Engl J Med. 2016 Mar 4. PubMed PMID: 26943629. 

  8. Wikan N, Smith DR. Zika virus: history of a newly emerging arbovirus. Lancet Infect Dis. 2016 Jul;16(7):e119-26. doi: 10.1016/S1473-3099(16)30010-X. Epub 2016 Jun 6. Review. PubMed PMID: 27282424. 

  9. Grubaugh ND, Andersen KG. Navigating the Zika panic. F1000Res. 2016 Aug 4;5:1914. PubMed PMID: 27746903. 

  10. Govero J, Esakky P, Scheaffer SM et al. Zika virus infection damages the testes in mice. Nature. 2016 Oct 31. doi:10.1038/nature20556. PubMed PMID: 27798603. 

  11. Duffy MR, Chen TH, Hancock WT et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. N Engl J Med. 2009 Jun 11;360(24):2536-43. doi: 10.1056/NEJMoa0805715. PubMed PMID: 19516034. 

  12. Real time RT-PCR is a way to detect and quantify RNA levels 

  13. Murray KO, Gorchakov R, Carlson AR et al. Prolonged Detection of Zika Virus in Vaginal Secretions and Whole Blood. Emerg Infect Dis. 2017 Jan 15;23(1). doi: 10.3201/eid2301.161394. PubMed PMID: 27748649. 

  14. The WHO’s Fact Sheet on the Zika virus 

  15. Checked on 29.10.2016 on PubMed 

  16. Dittmer DP. Zika vaccine: Clinical trial and error? Science. 2016 Sep 23;353(6306):1375. PubMed PMID: 27708030. 

  17. Abushouk AI, Negida A, Ahmed H. An updated review of Zika virus. J Clin Virol. 2016 Oct 3;84:53-58. doi: 10.1016/j.jcv.2016.09.012. Review. PubMed PMID:27721110. 

  18. Barrows NJ, Campos RK, Powell ST et al. A Screen of FDA-Approved Drugs for Inhibitors of Zika Virus Infection. Cell Host Microbe. 2016 Aug 10;20(2):259-70. doi: 10.1016/j.chom.2016.07.004. Epub 2016 Jul 28. PubMed PMID: 27476412. 

  19. Xu M, Lee EM, Wen Z et al. Identification of small-molecule inhibitors of Zika virus infection and induced neural cell death via a drug repurposing screen. Nat Med. 2016 Oct;22(10):1101-1107. doi: 10.1038/nm.4184. PubMed PMID: 27571349. 

  20. According to Dr. Aberle from the Medical University of Vienna (27 from Vienna, 2 from Innsbruck) on the 25th of October 2016