Doctor Q&A: Can pickled vegetables increase the risk of cancer? Dr Renee Hoenderkamp answers your questions

Can pickled vegetables increase the risk of cancer? I think I am being overly paranoid but I've read some concerning research online and I have a lot of it in my diet

This is a really interesting question and a little hard to assess as the studies are mixed and there may be many contributing factors, for example there seems to be a country/cultural influence. Let me explain…

There was a big look at research in 2020 that did show 'a significant association between increased gastric cancer incidence risk and high intake of pickled vegetables'. The risk increased with every 40 per day eaten comparing the highest to the lowest intake. A similar result was found with salted fish intake. The data seems stronger in countries in the Far East where they eat high amounts of pickled veg and salted fish.

So studies do show higher risks of esophageal/gastric cancers in areas with high consumption of pickled food.

For example, in high-risk areas of China, where pickled food is eaten daily as an important daily part of the family diet. It seems that fermenting moist veggies in jars for a few months can potentially yield cancer causing compounds such as N-nitroso compounds and mycotoxins.

These results seem to be repeated in several studies and the cancer support groups such as Macmillan do list pickled veg as a risk. However, in the UK and Europe the most important risk factors are:

• Being Male
• Being over 75
• Helicobacter pylori infection
• Smoking
• Diet inc pickled veg and salted fish
• Obesity
• Family history

So, on balance I think the answer is that eating a diet high in pickled vegetables does bring a degree of higher risk of gastric cancer and I think I would return to my mantra of everything in moderation, so if you can cut it down a bit, or enjoy every now and again rather than daily, you are managing a risk versus actually living life!

I have read about a link between the gut microbiome and autism - can this possibly be true? 

This is a fascinating question. As I have become more interested over the last few years in the gut microbiome, I too have read these reports about autism. And as I seem to see more children with a neurodiverse diagnosis, it has me feeling that there must be some environmental involvement. So I had a dive into the current data/research…

The first thing to say is that it is a complex, multi-directional relationship and that much more research is needed.

However, autism spectrum disorder (ASD) is a neurological disorder that affects normal brain development. There have been recent findings around the microbiota–gut–brain axis that suggest that gut microbiota (the type of bacteria, good and bad, that live in your gut) can influence many neurological disorders such as ASD. In fact, many studies have shown that early gut microbiota formation, method of delivery (vaginal or c-section), and early antibiotic usage significantly affect the gut microbiome and potentially the onset of ASD.

Early gut microbiome formation

That nine months growing a new human is more important that it might appear. The development of the baby’s gut microbiome is the same as the mothers so any stresses on the mother; poor diet, maternal stress, metabolic stress and antibiotics can affect this adversely and so affect the baby’s microbiome from which its future health path will develop.

Vaginal delivery v c-section

When a baby is born its gut microbiome undergoes a rapid ‘colonisation’ whereby the immature gut microbiome develops. This early development from birth to three years may have critical impact on the lifelong health of the child/adult. There is evidence that passing through the vagina delivers very different microbes compared to c-section delivery and the resulting colonisation differs in crucial bacteria which appear to affect neurodevelopment. For the individual bacteria see the study below. There is an increased risk of ASD in babies born by c-section.

Antibiotic usage

Antibiotic use during the formative years (nought to three) can disrupt the development of immune-mediated, metabolic, and neurological diseases and can impact the maturation of the immune system and have a damaging effect on typical microbiota establishment with long-term consequences. Studies using early antibiotics showed significant changes in gut microbiota, which could be directly responsible for turning on or off certain genes and this may affect the autism gene, potentially facilitating the development of ASD

The role of antibiotics and the microbiome is explored across a range of diseases, not just ASD, in a large systemic review of 22 million children below and is fascinating.

These changes in the gut microbiome appear to affect neuro-transmitter function and there is evidence that the gut microbiome of children with ASD is different to children without. The ASD microbiome appears to be distinctive and have an underdeveloped range and volume of gut bacteria unrelated to diet. They have fewer bacteria linked to neurotransmitter activity and five species of bacteria that aren’t typically found in the gut of children without the condition according to the researchers.

In 2019 the FDA in the USA labelled faecal transplant therapy a ‘fast track’ treatment for children with ASD so encouraging were the studies. If there is a characteristic microbial profile for ASD, this is promising for treatment for a life-affecting condition.

Clearly much more research is needed and it is clear that there are many intertwined and contributing causes but if we can see new treatments alongside early education regarding the adult microbiome, food, exercise and the role of antibiotics, the future may be brighter for ASD.

Is there a less invasive procedure for the smear test than the current one? I have been putting it off for years because it's so painful 

I am so sorry that you have had such a bad experience, sadly this is not unusual, especially for women at either end of the fertility age range. So younger women who have not had sex often/or at all or have vaginismus often struggle but the group I see struggling the most are women over the age of 40 who are peri-menopausal and are having some vaginal dryness that can make it excruciating. If this is you, I do have a suggestion…

Just before we get to that, to explain to those who don’t know, a Cervical smear is a test for women to identify/treat cervical cancer. The cervix is the opening to the womb, and a plastic speculum is inserted in to the vagina to open it up enough to see the cervix and to use a brush to take some cells for the lab. In the lab, they look at the cells to identify pre-cancerous cells early enough to make it a very treatable cancer if the smears are carried out at the correct intervals. You will get an invite every three years if you are aged 25 to 49. After that, you get an invite every five years until age 64. For Wales and Scotland – you get an invite every five years if you are aged 25 to 64. So now we have to ensure that you are comfortable enough to have the test.

So, for women suffering vaginal dryness that makes a smear test too uncomfortable to bear, I always prescribe a vaginal oestrogen for a month before the test. My favourite is estriol cream, applied daily for three to four weeks and usually this is enough to make the pain go away and allow what is a very useful test. You can use the pessary, vagifem, but if you are very dry, I find they don’t dissolve and so don’t do the job as well as the cream.

There is another light on the horizon with a self-taken swab which is much more acceptable and studies show, just as accurate. Trials were carried out in 2021 and the results are being analysed now, with a view to rolling this out. There is more information here.

Meantime, please speak to your doctor re estriol if this is the problem as it is an excellent screening test and may save your life. Good luck!