Expert Breakfast Report for April 5th 2023: Prof. Sheila Skeaff, Dept of Human Nutrition.

Good nutrition is important for everyone, and a talk that included some excellent general advice, plus specifics about diets and supplements - and advice on how to learn a lot more - hit the spot beautifully.

Sudbury’s Pink Snow

Prof. Skeaff started by asking the members present where they thought she had been born - and the country of origin was correctly identified as Canada. More specifically, she was born in the small mining city of Sudbury, ‘the Nickel Capital of the World’. In the early days of mining, many trees were cut down to melt the ore, and in that process, volumes of sulphur dioxide released into the atmosphere produced acid rain. Because of the prevailing wind, this resulted in one half of the town looking like a moonscape, while the other part was lush and green. “The most interesting thing, though, was, when I was a child, when it snowed, the snow was pink . . . . . Later, they built a ‘superstack,’ which took the smoke further away - more towards the U.S. actually - and the snow was white, and we could eat the snow from that day on!”

The Sudbury Superstack — Image by: supplied by Prof. Skeaff

Very interested in science when growing up, Sheila started at University. While unsure exactly what she wanted to do, certainly not thinking of Health Sciences, she thought she might like to be a teacher. “My mother said, ‘No! ’”. - She wanted me to be a Pharmacist, which did not appeal to Sheila, and she studied Human Biology. In her second and third years, she discovered Human Nutrition as a discipline, “and I really liked it - it has Science, but it also has the people element, in the sense that everybody eats . . “ 

Moving on to an MSc. at Guelph University, she then emigrated with her husband to New Zealand.

Prof. Skeaff commented further on the choice of a career, noting that some people fixed from an early age on what they wanted to do, while others, such as herself, were less sure at an early age. “I have also taken a lot of breaks between my studies.” This amounted to a year between first degree and Masters, the 8 years between Masters and Ph.D. “Take time off to do other things. You’ll still get there . . I worked part -time for some time and had kids . . .you can do lots of things . . take the time, enjoy it. . . There are lots of ways to get somewhere. . . If you don’t get in (to Health Sciences), no big deal, get your degree. Try again - if you don’t get in then . . . try being an allied health professional, and try again later. You will get there eventually. And maybe along the way you will find some other field you like. Do not be discouraged. There’s plenty of time.”

“I do notice what people eat - I try not to judge what they eat, because I don’t want them to judge what I eat!” In Nutrition, as in other areas, the focus goes around. For example, vitamin D at one time as considered the cure-all for everything - cancer, asthma, anxiety. At present, the microbiome has centre stage. But the basic stuff remains the same.

Research Interests

When asked to speak a little more on her own interests in Nutrition, Prof. Skeaff talked about her Masters research first. Sheila encouraged people to undertake higher degrees, urging people not to be afraid of writing a thesis. A thesis is no more than a long essay, plus there was lots of time to complete it, and people (supervisors) around to help with the process. Her Masters was a laboratory study on the influence of zinc and copper in cell growth. Along with tissue culture work, live rats were used, and had to be killed to complete the study. While this was all done to ethical standards, “It was an experience I didn’t enjoy.” - not only working in the laboratory, but using the animals and having to kill them. That lead to her Ph.D. study, after some time off, studying iodine in people. The soil of New Zealand is low in both selenium and iodine, and in the 1920’s medical researchers at Otago University found that about 1 in 3 children, especially in the South Island, had a goitre (thyroid gland enlargement), which are a direct result of low iodine intake. 

A Goitre

This led to the use of iodine in salt, since it is cheap, and just about everyone has salt in or on their food. One of the problems of low dietary iodine is that the developing foetus of an iodine-deficient mother may not develop full brain capacity.

While iodised salt solved the problem at the time, it returned in the 1980’s-1990’s.

Around 2009, manufacturers began using iodised salt in bread making, instead of the plain salt used previously. Once again, a fairly cheap staple food item meant that almost everyone would be boosting iodine intake. Responding to questions relating to this, Sheila noted that seafood is also a good source of iodine, notably sushi, with its seaweed wrappers, as illustrated by the generally high levels of iodine found in Japanese people.

More recently, Prof. Skeaff has been working on food waste measurement (including some studies on food waste at St. Margaret’s). About 30-40% of food globally is wasted, which is a huge strain on the environment, with all the time and energy spent growing and distributing the food, only for a large part of it to be thrown away. On top of that, the waste in landfill generates methane gas, adding to the problem of climate change. And at the same time, there are people going hungry. Sheila’s group has recently been given a modest grant to measure how much food is wasted throughout New Zealand “in every single sector. . . . The U.N. goal is to reduce food waste by half by 2030”, so we need to find out the current situation.

Commenting on the waste food study done at St. Margaret’s last year, Prof. Skeaff noted that discussions with students indicated that they had been aware of, and avoided, food waste at home, but were less inclined here, perhaps due to the environment, and possibly having set meal times was a factor.


Asked if three large meals a day was better than ‘grazing’ throughout the day, Sheila told us it doesn’t make any difference, “Whatever suits you best”. Another question concerned fasting, and Sheila said how it was interesting that more immigrants to New Zealand had experience of this, mentioning Ramadan as an example of religious fasting, a period during which devotees fast from both food and water during daylight hours. There are also other groups, such as Ethiopians, who often have short-term fasts. Intermittent fasting. of course, is used by people in an effort to lose weight. “There is no harm (in fasting), let me put it that way!” said Prof. Skeaff, “Some people lose weight, some maintain their weight, and others gain weight . . If you make up for it (fasting during the day) and you are eating all night long, you can see how that is not beneficial - especially if you are eating treat foods as a reward for fasting.” Studies indicate that strategies such as 5-2 (5 days eating normally and 2 days fasting) can help with weight loss.

Diets such as the Paleo and Keto, in which carbohydrates are restricted, can certainly produce weight loss,”but we do have an obligate need for some carbohydrate - the brain does. The more restricted the diet is, the more difficult they are to follow, and you can get rebound.” In particular, Prof. Skeaff commented on the Keto diet, with its exceedingly low carbohydrate content, “you also shed water. and you can lose muscle protein, which isn’t good. And then when you go off it, the water comes back again - and you have lost muscle. And you don’t want to lose muscle.” [Short term weight change is generally due to the water content of the body - Ed.] Sheila’s advice on weight loss dieting is to pick a method that works for you. “The key thing is to maintain weight loss. - The best thing is not to gain weight! . . . and it doesn’t take much to gain weight. A hundred grams a year adds up over time to kilograms.”

Asked when the Keto diet might be appropriate, Prof. Skeaff told us it was originally developed to help children with epilepsy - and is still used for children failing to respond to drug therapy. “Most Nutritionists and Clinicians are not fans of the Keto diet. First it’s very restrictive, and is very hard to follow, and second, people tend to interpret the ‘high fat’ part in terms of saturated fats, which is not good for heart disease.” Studies, especially in middle-aged people, show the Keto diet adversely affects levels of blood lipids. A modified Keto diet can be good for weight maintenance. Asked about the Raw Food Diet, Prof. Skeaff was unimpressed by it, suggesting that it might be a reaction to processed food. She pointed out that there is a need to process some food. She talked then about the ‘impossible burger’, made entirely from plants, and the fact that cooking foods in many cases enhances the flavour.

Impossible burger — Image by: from 'Impossiblefoods' web site

Supplements, Students, and More on Diets

On the topic of supplements, Sheila said there is nothing wrong with taking multivitamin multimineral supplements from a reputable source and good quality control ensured by the manufacturer. “You should always buy them from a reputable company, such as Healtheries, Blackmore’s or Centrum. But if you are eating a good diet, such as that supplied at St. Margaret’s, you don’t need them. Medically prescribed single supplements are a different issue. Ones such as iodine for pregnant women, iron for iron deficiency anaemia, etc. should certainly be taken. Pregnant women are generally given folic acid, although now that is being incorporated into commercial bread, it may not be necessary (1).

Asked if there was a particular group of students she liked working with, Sheila said she likes working with all students, but especially Post-Graduate students, because you really get to know them as people and form a relationship with them - in contrast to most taking early papers, which have large numbers of students who may only take that one Nutrition paper. She went on to describe a couple of occasions when she had travelled overseas with students, including going to Vanuatu with a Masters student from West Papua. They worked together for 10 days on the diet of the local children and looking at their teeth. This student taught Sheila how to cook green bananas, “which was really useful. “I’m a big fan of green bananas now.” Also in Japan with a Singaporean Ph.D. student who was very conversant with technology, enabling them to get about and see the sights. “We had a great time together.” On the topic of deer velvet, Sheila said she had not studied it as a supplement, in that “it’s used for other circumstances than supplementing your diet with nutrients.”

Meat Intake and Climate Change

Supplements in the sport context led to her commenting on surveys of the national New Zealand diet which showed males in particular ate about twice as much protein as they actually need, so are already on a high protein diet. Indeed, in a discussion with one of her male students recently about cooking (“Everyone should cook.”), it emerged that he eats 400 g of mince every day - four times the daily requirement. Sports supplements are an easy, convenient way of supplying protein, while generally will not do harm - except you need to be confident they do not contain any banned substances. “That has happened to people in competition. Our view is that you don’t need them - I’m not talking about the elite people.”

Describing herself as one who eats a mainly vegetable diet with a small amount of meat, (trendy term = ‘flexitarian’), Sheila responded to a question concerning vegan and vegetarian diets having less effect on climate change than ‘normal’ diets. First she commented on “a lot of evidence” indicating that Vegans/vegetarians have lower weight, lower risk for cardiovascular disease and other non-inherited diseases such as cancer.

In addition, having a plant-based diet means a markedly lower carbon footprint that meat-containing diets, owing to the inefficiency of fodder conversion by animals to edible meat. “All the recommendations that come from every group and organisation now are suggesting that people reduce their meat intake, particularly beef and lamb.” But the story is not a simple one. “It’s such a tricky thing when you are talking about the environment, because there are downsides to everything. You’ve got to look at what’s called the ‘life cycle’ of the item under scrutiny.” ‘Life cycle’ here refers to all the factors involved from the beginning of the item to its end, including packaging, shipping, etc. There are so many factors that a lifecycle assessment (LCA) is often not done. In the case of almond milk, for example, since almonds are not grown here, they must be shipped from elsewhere. Once the ‘milk’ has been extracted, using energy consuming methods, there is a large amount of waste material that must be disposed of. “I think if anyone can be a vegan, I really admire them - it’s hard.” (One of the members present, when asked, stated she had been a vegan for 6 years).

Prof. Skeaff asked if St. Margaret’s had any meatless days in the week, such as ‘Meatless Mondays” (2). (It does not). Tried in some Colleges, “Meatless Monday” had not been well received, and the name was changed to ‘Mindful Monday’, which turned out to be more acceptable. The point here is that if we all reduce meat consumption, this will have a positive effect on factors involved in climate change.

Antonia encouraged those present to take HUNT141, as it is a “typical 8th paper for you Health Sci’s.” Sheila (though clearly a little taken aback by Antonia’s unexpected tribute) commented that the top 10 students last year had also all obtained places in their desired Health Science courses, and in any event, it was providing knowledge that would be useful for the rest of one’s life.

1. - Iodine deficiency in pregnancy: the effect on neurodevelopment in the child. Sheila Skeaff.


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Posted: Wednesday April 12, 2023