Interview conducted by Anne Wright, Registered Dietitian
Dr Caroline Childs is a Lecturer in Nutritional Sciences at the University of Southampton. Dr Childs’ research to date has investigated nutrients including dietary fatty acids, probiotics, and prebiotics. Experimental approaches have included assessment tissue composition, immune function, inflammatory status, immunosenescence, and the gut microbiota. Dr Childs is currently a Member of the ILSI Europe Expert Group on Immune Competence and Co-Chair of ILSI Europe’s Nutrition, Immunity and Inflammation Task Force. You can find out more about Dr Childs here.
Nutrition and immunity is an emerging, and sometimes controversial area. I asked Caroline why she thinks there has been so much recent interest in this area. “The current COVID-19 pandemic has really brought immune function to the forefront of many people’s minds,” she told me. “Diet is just one of many factors affecting the immune system. Other factors like genetics, age and previous exposures to illnesses will also alter your immune system. Diet is however, one of a few factors which we can as individuals have a degree of control over”.
I asked Caroline about her research area. “My research investigates how foods or nutrients can affect our immune system” she told me. “This has included studies of omega-3 fatty acids, probiotics and prebiotics, immune function and gut health (see appendix for publications). I hope my research can help to inform the public and has potential for improving population or individual health”.
One of Caroline’s most recent studies looked at the impact of synbiotics on responses to the flu vaccine1. I asked her to tell me a bit about the methods used and how she analysed the data in this study. “During this study, we provided healthy volunteers with a synbiotic (prebiotic and probiotic) supplement for 8 weeks and investigated whether this affected their response to the influenza vaccination” she told me. “One of the methods I use often is flow cytometry – this allows me to look at the size and density of immune cells, and I can use fluorescent markers to identify which kind of immune cells they are, whether they are activated or not, and whether they are producing molecules like inflammatory cytokines. This gives me a huge amount of data, as we look at least 10,000 cells, and can have 14+ different measures of each cell, so analysis can be time consuming and complex. There’s also a degree of subjectivity even in scientific measures, which makes good record keeping and consistent staff training so important.”
I was curious to know if Dr Childs had encountered any other challenges along the way. “Yes,” she replied. “One of the main challenges (and joys!) working on immune function is its complexity. Your immune system involves multiple levels of action, ranging from the physical barrier your skin provides to stop bacteria entering your bloodstream, to the highly specific signals your immune cells can produce to attract other cells to an injury site. There are challenges in translating findings to the public – for example, if I told you I could take your influenza antibody titre from 100 to 200 with probiotics, is that meaningful to you? There are also financial challenges, immune research is expensive in terms of the equipment and consumables required to perform high quality research”.
I was keen to know how we can translate the findings of Caroline’s research into practice. “It’s clear that nutrition can directly affect your immune system, by providing it with essential fuel and building blocks, or indirectly via effects of diet on the microbiome” Caroline responded. “Ultimately, current dietary advice such as consuming 5 fruits and vegetables a day, choosing wholegrain carbohydrates, and eating fish as well as maintaining a healthy body weight are all consistent with how we can optimise our immunity. The challenge is that we aren’t generally very good at following this advice. I think there are important roles for policy makers in setting recommendations, legislation and marketing around foods to ensure that our food environment supports healthy choices”.
But what about vitamin and mineral supplements and immune support? Caroline says there could be a role for supplements, when needed. “In an ideal world, we would all have the tools we need to follow a healthy, high fibre diet, rich in fruits and vegetables” she told me. “However, there are times when pragmatic decisions have to be made. Many people face challenges in making healthy choices, perhaps for financial reasons, or due to physical reasons such as reduced appetite in later life”.
We must remember that there are many immune-related diseases which can’t be prevented or treated with supplementation or diet alone, (e.g. asthma or rheumatoid arthritis). “That said, there are examples of when supplements can be beneficial to immune function – for example, those with zinc deficiency can gain immune benefits by use of supplements. There are also some interesting links between vitamin D and immune function. Our diet is just one source of vitamin D. Our vitamin D status is influenced by UV exposure, skin pigmentation, and obesity. All UK adults are advised to consider taking a supplement of 10ug vitamin D through the autumn and winter period, and year round for those at greater risk of deficiency such as those who have little sun exposure or darker skin”.
So will supplements make us feel better? I asked. “It's important that we consider the subjective impact of such interventions,” Caroline explained. “One challenge of evaluating the efficacy of dietary and lifestyle interventions on immune function research is that people can’t really ‘feel’ if their immune system has improved. Although we may see longer term impacts such as whether they develop a cold/flu over the winter period”.
I’ve seen a lot of marketing around “immune boosting foods” so I asked Caroline for her take on this. “Immune boosting is a controversial term, and ‘immune support’ is a much more appropriate aim in my opinion. Boosting implies turning up immune function, which could be beneficial if you’re an older adult with a poorly responsive immune system, but could be disastrous if you were suffering from inflammatory disease or the cytokine storm seen in cases of severe COVID-19”.
“In terms of marketing based on immune support, there are controversies and complications, as we eat foods not just individual nutrients. So, for example, if a yoghurt is supplemented with vitamin D to allow it to make the claim that it supports your immune system, but also contains a high amount of added sugars, it becomes controversial. Wholefoods don’t have marketing budgets in the way the processed foods do. We don’t often see attractive labelling on our bag of satsumas or frozen peas promoting the potential health benefits of eating them”.
Caroline told me diet is just one factor impacting immunity. “We should take a combination of steps such as trying to follow a healthy diet, maintaining a healthy weight, being physically active and having the recommended vaccinations for later life (e.g. for the flu or shingles). Lack of sleep and stress can have an impact on our mental and physical health, and it’s very likely that immune effects are components of these responses. Also important are the benefits to mental and physical wellbeing of activities such as gardening or pet ownership – there are plausible mechanisms by which these may further benefit your immune system via your microbiome”.
This is such a fascinating area of research. I wanted to know “what next?” for Caroline. “I hope to continue to grow my research team,” she told me. “It’s a real highlight of my job to see PhD students and young researchers professionally develop. Over the next year I hope to launch new studies of nutrients and the immune system, and to build collaborations with my colleagues with other areas of expertise”. I’m sure I’m not alone in saying that I can’t wait to see the results of these studies!
Del Fabbro S., Calder P., & Childs C. (Accepted/In press).Microbiota-independent immunological effects of non-digestible oligosaccharides in the context of inflammatory bowel diseases. Proceedings of the Nutrition Society. 2019.
Scorletti E., Afolabi P., Miles E., Smith D., Almehmadi A., Child, C. Alshathry A. et al. Synbiotic alters fecal microbiomes, but not liver fat or fibrosis, in a randomized trial of patients with non-alcoholic fatty liver disease. Gastroenterology. 2020: 158(6), 1597-1610.e7.
Lillycrop K., Garratt E., Titcombe P., Melton P., Murray R., Childs C. et al.Differential SLC6A4 methylation: a predictive epigenetic marker of adiposity from birth to adulthood. International Journal of Obesity. 2019; 43(5), 974-988.
Przemska-Kosick, A., Childs C., Maidens C., Dong H., Todd S., Gosney M.et al..Age-related changes in the natural killer cell response to seasonal influenza vaccination are not influenced by a synbiotic: a randomised controlled trial. Frontiers in Immunology. 2018:9, 1-9. .
Lillycrop K., Murra R., Cheong C., Teh A., Clarke-Harris R., Barton S., Childs C. et al.ANRIL promoter DNA methylation: a perinatal marker for later adposity. EBioMedicine. 2017: 19, 60-72.
Enani S., Przemska-Kosicka A., Childs C., Maidens C., Dong H., Conterno L. et al.Impact of ageing and a synbiotic on the immune response to seasonal influenza vaccination; a randomised controlled trial. Clinical Nutrition. 2017: 1-33.
Godfrey K., Cutfield W., Chan S-Y., Baker P., Chong Y., & NiPPeR Study Group.Nutritional Intervention Preconception and During Pregnancy to Maintain Healthy Glucose Metabolism and Offspring Health ("NiPPeR"): study protocol for a randomised controlled trial. Trials. 2017:18, .
Przemska-Kosicka A., Childs C., Enani S., Maidens C., Dong H., Bin Dayel I., et al.Effect of a synbiotic on the response to seasonal influenza vaccination is strongly influenced by degree of immunosenescence. Immunity & Ageing. 2016; 13, .
del Bas J., Caimari A., Rodriguez-Naranjo M., Childs C., Paras Chavez C., West A.,Calder P.Impairment of lysophospholipid metabolism in obesity: altered plasma profile and desensitization to the modulatory properties of n-3 PUFAs in a randomized controlled trial. American Journal of Clinical Nutrition. 2016; 104(2), 266-279.
Polus A., Zapala B., Razn, U., Gielicz, A., Kiec-Wilk, B., Malczewska-Malec, M., et al.Omega-3 fatty acid supplementation influences the whole blood transcriptome in women with obesity, associated with pro-resolving lipid mediator production. Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids. 2016: 1861(11), 1746-1755.
Razny U., Kiec-Wilk B., Polus A., Goralska J., Malczewska-Malec M., Wnek D., et al.Effect of caloric restriction with or without n-3 polyunsaturated fatty acids on insulin sensitivity in obese subjects: a randomized placebo controlled trial. BBA Clinical. 2015; 1-7.
Phillips M., Childs C., Calder P., & Rogers, P..No effect of omega-3 fatty acid supplementation on cognition and mood in individuals with cognitive impairment and probable Alzheimer's Disease: a randomised controlled trial. International Journal of Molecular Sciences. 2015:16(10), 24600-24613.
Massot-Cladera M., Costabile A., Childs C., Yaqoob P., Franch A., Castell M., & Pérez-Can, F.Prebiotic effects of cocoa fibre on rats. Journal of Functional Foods. 2015:19, 341-352.
Child C., Kew S., Finnegan Y., Minihane A., Leigh-Firbank E., Williams C., & Calder P. Increased dietary alpha-linolenic acid has sex-specific effects upon eicosapentaenoic acid status in humans: re-examination of data from a randomised, placebo-controlled, parallel study. Nutrition Journal. 2014; 13(113), 1-5.
Daud N., Ismail N., Thomas E., Fitzpatrick J., Swann J., Costabile, A., et al.The impact of oligofructose on stimulation of gut hormones, appetite regulation, and adiposity. Obesity. 2014; 22, 1430-1438.
Fisk H., West A., Childs C., Burdge G., & Calder P.The use of gas chromatography to analyse compositional changes of fatty acids in rat liver tissue during pregnancy. Journal of Visualized Experiments. 2014;, e51445-e51445.
Childs C., Röytiö H., Alhoniemi E., Fekete A. A., Forssten S., Hudjec, N., et al.Xylo-oligosaccharides alone or in synbiotic combination with Bifidobacterium animalis subsp. lactis induce bifidogenesis and modulate markers of immune function in healthy adults: a double-blind, placebo-controlled, randomised, factorial cross-over study. British Journal of Nutrition. 2014; 111(11), 1945-1956.
Maneerat S., Lehtinen M., Childs C., Forssten S., Alhoniemi E., Tiphaine M., et al.Consumption of Bifidobacterium lactis Bi-07 by healthy elderly adults enhances ex-vivo phagocytic activity of mono- and granulocytes. Journal of Nutritional Science. 2013; 2, e44.
Childs C., Hoile S., Burdge G., & Calder P.Changes in rat n-3 and n-6 fatty acid composition during pregnancy are associated with progesterone concentrations and hepatic FADS2 expression. Prostaglandins, Leukotrienes and Essential Fatty Acids. 2012; 86(4-5), 141-147.
Phillips M., Childs C., Calder P., & Rogers P.Lower omega-3 fatty acid intake and status are associated with poorer cognitive function in older age: a comparison of individuals with and without cognitive impairment and AD. Nutritional Neuroscience. 2012; 86, 271-277.
Childs C., Fear A., Hoile S., & Calder P..Different dietary sources of omega-3 DHA during pregnancy and in the developing rat brain. OCL - Oléagineux, Corps Gras, Lipides. 2011; 18(5), 259-262.
Garcia-Larsen V., Luczynska M., Kowalski M., Voutilainen H., Ahlström M., Haahtela T., Childs C et al.Use of a common food frequency questionnaire (FFQ) to assess dietary patterns and their relation to allergy and asthma in Europe: pilot study of the GA(2)LEN FFQ. European Journal of Clinical Nutrition. 2010:65(6), 750-756.
Childs C., Romijn T., Enke U., Hoile S., & Calder, P..Maternal diet during pregnancy has tissue-specific effects upon fetal fatty acid composition and alters fetal immune parameters. Prostaglandins, Leukotrienes and Essential Fatty Acids. 2010; 83(4), 179-183.