Introducing Fat

Fats are trendy but they are not all the same. Different fats affect the body in different ways – there are good fats, not so good fats and bad fats

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Fat for fuel

Fats provide fuel for the body.  From the three macronutrients, fat provides the greatest amount of energy per kg.  This is twice as much as the same weight of carbohydrate or protein.

The word fat refers to both fats and oils

Fats are trending and topical because of uncertainty within the research arena but a common theme is there are healthy fats which we should all eat along with a good dose of vegetables.
Foods with a high-fat content include butter, cream, nuts, olives, avocados, seeds, eggs, cheese and obviously fatty meats, salami, sausages.

What do fats do?

Fats provide energy for the body and the brain.  Eating too much fat will make you fat, but fat is an essential component of the diet.

  • Fats are valuable for transporting fat-soluble vitamins and fat-soluble anti-oxidants around the body.
  • Fats are integral to the cell structure – the cell membrane is made up primarily of fat.
  • Fats insulate body organs
  • Fats are involved in the manufacture of hormones

Fats have many functions and there are different types of fat. Fats are categorised by their chemistry and can be considered either healthy or unhealthy.

categories of fats, saturated, unsaturated
Fats are categorised based on their physical chemistry.   Unsaturated fats contain at least one double bond in the carbon chain whereas saturated fats contain only single bonds.  Mono-unsaturated has one double bond, poly-unsaturated has more than one double bond.  Omega-3 and omega-6 indicate the placement of the first double bond.

Fats have different structures

Understanding fat is about understanding the physical structure of the fat, in particular triglycerides, which are the main type of fat in the diet.

A triglyceride is three fatty acids held together by a glycerol.  Think of an “E” – the vertical part is the glycerol and the three horizontal bars are the fatty acids.  The fatty acids attached to the glycerol can be the same or different.

A fatty acid is a chain of carbons with hydrogens attached.  It is the way those carbons are holding hands which defines whether it is saturated or unsaturated.  The saturated fatty acid has a simple hand hold whereas the unsaturated fatty acid has a more intricate handhold.  It may be a mono (single) or poly (many) handholds in a ‘cis’ or a ‘trans’ grip.

The length of the fatty acid – short, medium or long chain fatty acid – determines the melting point of the fat.  A long chain fatty acid will have a lower melting point and will be liquid at room temperature e.g. oils and a short chain fatty acid will have a higher melting point and will be solid at room temperature e.g. butter. The medium chain fatty acid is in between e.g. coconut oil.

The length of the fatty acid determines whether the fat is solid or liquid at room temperature and the type of carbon bonds (handholds) determine the fats saturation.

Recommended daily intake of total fats

A total fat recommendation has not been set by New Zealand Ministry of Health as it is the type of fat consumed which is important rather than the overall fat intake but there are guidelines of between 20 – 35% of energy intake (1).  Eating insufficient fat can be detrimental to maintaining weight and it becomes very difficult to meet all nutritional requirements (1).

Using the above guidelines 20 – 35% of total energy intake for a 30 year old woman (1.6 m high) with mild physical activity requires 8800 kJ/day of energy this equates to 47 – 83 g of fat per day.

Nutrition Information Panel

Total fat content is required on the New Zealand Nutrition Information Panel per 100g of food and per serving.  Saturated fat is also required as a separate entry.

On the chocolate Nutrition Information Panel below, it has nutritional information per serving (20 g), % daily intake of the three macronutrients per serving and per 100 g of chocolate.  The fat in 20 grams of this chocolate provides 7% of your suggest fat intake based on a daily intake of 8700 kJ and a suggested total fat intake of 32% of total energy.

Nutrition Information Panel

Nutrition Information Panels are confusing, perhaps a blog on Nutrition Information Panels is required – sign up for an alert when my Foodproof blogs are released.

Summary

Food confusion is evident with fat, the science is changing and the literature is not clear on the right direction.  Fats are vital to our diet and understanding the difference between good and not so good fat is a great start.  From here, it becomes easier to focus on replacing the not so good fats with the good fats in the diet.

This blog has touched on the differences in the structure of fat. The next blog will look more closely at saturated fats – sign up by email.

Reference

  1. Ministry of Health, National Health and Medical Research Council. Nutrient reference values for Australia and New Zealand including recommended dietary intakes: NHMRC Publications, 2005.
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Project Salt Incognito

Why are they taking salt from our food?

Salt or sodium?

The only thing that differentiates table salt, sea salt, rock salt, Himalayan rock salt or organic salt is a few minerals and a marketing strategy – they are the same thing.  Salt or sodium chloride is the primary source of sodium for the human body.

Sodium Chloride has two elements –
sodium (40%) and chloride (60%)

Sodium is a key component of our body for regulating fluids i.e. our blood volume.  Too much sodium increases the volume of the blood (by attracting water) thereby adding stress to the blood vessels and heart (more blood to pump around) and resulting in increased blood pressure.  The connection between high blood pressure and increased risk of strokes, cardiovascular disease has been firmly established (1).

What is the evidence?

Initially, it was the Intersalt observational study (2) which found the association between sodium and blood pressure.  Since then many randomised controlled trials have been organised to test this association.
Evidence of sodium intake affecting blood pressure is definite.  The World Health Organisation (WHO) conducted a meta-analysis and systematic review. The overall objective was to assess the effect of reduced sodium intake on blood pressure, kidney function and blood lipids.  Other specific objectives include looking at the effect of consuming less salt compared with consuming more and reducing the salt by varying amounts to establish the best intake zone (3).

The meta-analysis of 37 randomised controlled trials showed a reduction in salt intake is very likely to reduce systolic blood pressure

  • in normotensive and more so in hypertensive people
  • regardless of how much the salt reduction was and
  • regardless of whether blood pressure medication was taken or not

A reduction in salt intake is able to reduce resting diastolic blood pressure.

For the greatest positive effect in systolic and diastolic pressure, the sodium intake was less than 2g (5g salt) per day,

The same meta-analysis also confirmed blood lipids (total cholesterol, HDL and LDL  and triglycerides) were not affected by changes in salt (3).

The evidence for reducing salt in the diet for healthy blood pressure and the evidence for raised blood pressure being a significant factor in strokes and cardiovascular disease is of high quality.

Population Health

The relationship between high salt intake and increased systolic blood pressure (and thereby cardiovascular disease) makes high salt intake a major population health concern.  WHO considers reducing daily salt intake will have significant health and financial benefits to the global population.  New Zealand modelling has found similar effects and NZ would benefit financially and in terms of life quality with population salt reduction.

1 gram of sodium chloride (salt) contains 390 mg sodium

WHO strongly recommends the intake of sodium be less than 2g/day (5g of salt).  This equates to a global target of a 30% sodium reduction with a targeted date of 2025 (4).

Current daily salt intake around the world is shown in the graph below – Australia 9.6g (5), New Zealand 8.4g (6), United States 8.3g (7) and United Kingdom 8.0g (8).

FP004 Salt intakes
The daily salt intakes in Australia, New Zealand, United Kingdom and the United States is well above the WHO recommendation of 5g/day

Global initiatives

The majority of sodium comes from processed foods and it is challenging to leave the salt out of food processing.  Changing the salt content in the food affects many things – taste, texture, shelf life and food safety.  Initiatives to reformulate food with this goal in mind has been undertaken globally.  Incognito salt reductions have already been accepted by consumers, up to 40% and 70% of salt has been removed from bread and processed meats (9).

Salt in the United Kingdom

The United Kingdom has actively been reducing salt in their food since 2003.  Voluntary salt reduction in food manufacturing, public awareness campaigns and mandatory labelling of high salt foods has resulted in a 15% reduction in salt intake since the work started (10).

Salt in Australia and New Zealand

The Healthy Food Partnership, comprising of the Australian Government, public health groups and the food industry is also working towards reducing salt by reformulating food.  Voluntary targets were set in 2009 for 10 food categories.  However, a 2017 study (11) found only 17 of 33 large Australian food manufacturers have publicly available strategies to reduce salt content in their foods.  The authors conclude insufficient efforts were being made to make “significant and comprehensive positive (nutrition) changes” in relation to salt or healthier food products”.

New Zealand has no government-led salt reduction strategy.  The New Zealand Heart Foundation (NZHF) has led the charge, urging voluntary reductions from manufacturers through the NZHF ‘Tick’, initiated in 1991.  This front-of-pack nutrition logo helps consumers determine heart-healthy foods and encourages ‘Tick’ food manufacturers to produce heart-healthy products.  Over a 12 month period (1998/1999) The Tick program resulted in 33 tonnes of salt being removed from food products (12).

In 2010, 50% of New Zealand and 72% of Australian bread had reduced sodium levels to below 450mg/100g or 1.1 g salt per 100 g of bread (13)).  Another New Zealand study demonstrated a 12% reduction in salt content in 182 foods over the 10 years to 2013 (14). The graph below shows different food groups and changes in salt quantity from this study.

FP004 food changes
Salt has been removed from many processed foods but some food groups have increased their salt levels

Even though Australia and New Zealand have voluntary salt reduction programmes (and have seen some results in the food chain) they have not yet reported reductions in population salt intake and it is considered that the WHO global target will not be met in 2025 (15).  This is not the case everywhere, 12 countries have reported reduced salt intakes in their population – will this correspond to reduced blood pressures?

New Zealand has a strong and committed non-government organisation, New Zealand Heart Foundation, to lead the salt reduction initiatives using food reformulation, front-of-pack labelling and consumer education but is this enough?  Do we need a government led salt reduction programme to provide more resources and maybe even legislate?

References

  1. Lewington S, Clarke R, Qizilbash N, Peto R, Collins R. Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies. The Lancet 2002;360(9349):1903-13.
  2. Intersalt Cooperative Research G. Intersalt: An International Study Of Electrolyte Excretion And Blood Pressure. Results For 24 Hour Urinary Sodium And Potassium Excretion. BMJ: British Medical Journal 1988;297(6644):319-28.
  3. World Health Organization. Effect of reduced sodium intake on blood pressure, renal function, blood lipids and other potential adverse effects. 2012.
  4. World Health Organisation. Global action plan for the prevention and control of NCDs 2013-2020. Geneva: World Health Organisation, 2013.
  5. Land M, Neal B, Johnson C, Nowson C, Margerison C, Petersen K. Salt consumption by Australian adults: a systematic review and meta-analysis. Medical Journal of Australia 2018;208(2):75-81. doi: 10.5694/mja17.00394.
  6. McLean R, Edmonds J, Williams S, Mann J, Skeaff S. Balancing Sodium and Potassium: Estimates of Intake in a New Zealand Adult Population Sample. Nutrients 2015;7(11):5439.
  7. Hoy M, Goldman J, Murayi T, Rhodes D, Moshfegh A. Sodium intake of the U.S. population, NHANES 2007-2008. In: Group FSR, ed. Dietary Data Brief: Food Surveys Research Group Dietary Data Brief No 8, 2011.
  8. Bates BC, L; Maplethorpe, N; Mazumder, A; Nicholson, S; Page, P; Prentice, A; Rooney, K; Ziauddeen, N; Swan, G. National Diet and Nutrition Survey: assessment of dietary sodium. Adults (19-64 years) in England 2014. London: Department of Health, 2016.
  9. Jaenke R, Barzi F, McMahon E, Webster J, Brimblecombe J. Consumer acceptance of reformulated food products: A systematic review and meta-analysis of salt-reduced foods. Critical Reviews in Food Science and Nutrition 2017;57(16):3357-72. doi: 10.1080/10408398.2015.1118009.
  10. Webster J, Trieu K, Dunford E, Hawkes C. Target Salt 2025: A Global Overview of National Programs to Encourage the Food Industry to Reduce Salt in Foods. Nutrients 2014;6(8):3274.
  11. Lindberg R, Nichols T, Yam C. The Healthy Eating Agenda in Australia. Is Salt a Priority for Manufacturers? Nutrients 2017;9(8):881.
  12. Young L, Swinburn B. Impact of the Pick the Tick food information programme on the salt content of food in New Zealand. Health Promot Int 2002;17(1):13-9.
  13. Dunford E, Eyles H, Mhurchu CN, Webster J, Neal B. Changes in the sodium content of bread in Australia and New Zealand between 2007 and 2010: implications for policy. The Medical Journal of Australia 2011;195(6):346-9. doi: 10.5694/mja11.10673.
  14. Monro D, Mhurchu C, Jiang Y, Gorton D, Eyles H. Changes in the Sodium Content of New Zealand Processed Foods: 2003–2013. Nutrients 2015;7(6):4054.
  15. Trieu K, Eyles H, Webster J. Salt reduction in Australia and New Zealand: How do we compare with the rest of the world? Journal of Nutrition & Intermediary Metabolism 2016;4:26-7.

Sugar and New Zealand children

Can we be more responsible for what our children eat?

  • High sugar intake is a known variable in the obesity equation
  • Obesity is expensive, avoidable, claims lives and life quality
  • New Zealand adults (and probably children) consume more dietary sugars than recommended by World Health Organisation

The cost of sugar

Obesity costs New Zealand NZ$ 624,000,000 per annum (last calculated in 2006) [1]. This is likely to be higher now as New Zealand has the third highest rate of obesity in the OECD – trailing behind the United States and Mexico.

These unnecessary healthcare costs come from the obesity-associated non-communicable diseases being type 2 diabetes and cardiovascular disease, gout and some cancers. More people die from non-communicable diseases (11.4%) than tobacco-related deaths (9.1%) and both are largely preventable. Life expectancy may have increased in the last 100 years but over the years gained 20 – 30% are lived in poor health [2].

Obesity is not an easy topic as there are many variables behind carrying too much weight. The drivers of obesity include diet, physical activity levels, maternal health (yes, your mother’s health during pregnancy), sleep and the obesogenic environment, where food supply and marketing promote high energy intake with energy-dense and nutritionally poor foods [3], [4].

New Zealand children

Obese children are likely to grow into obese adults. As well as the adult risks later in life, obese children have their own special health consequences: obstructive sleep apnoea, musculoskeletal problems, asthma and psychological problems (body dissatisfaction, poor self-esteem and depression) are all associated with child obesity. Additionally, their learning can suffer and they may be targeted for bullying [5].

FP003 BMI
Rates of obesity are higher in our Pacific and Maori children

Eleven out of 100 NZ children (2-14 years) are obese and another 21 (out of the same 100) are in the overweight category. Rates are higher in Pacific and Maori children – 61% and 44% respectively are overweight or obese [4].

What is even more disconcerting is 50% of parents of obese children do not believe their child is overweight – this is higher in obese children aged 2-4 years where 90% of parents do not consider their child to be neither under- or overweight [6].  This is another story!

High sugar intake is one of the determinants of a poor diet and a contributor to obesity. One-quarter of sugar in a child’s diet comes from sugar-sweetened beverages [7], which are of low nutritional quality leading to a poor diet, weight gain and associated risks. The consumption of high sugar food generally displaces the consumption of more nutritious foods and increases the energy intake.

Sugar Recommendations

New Zealand Ministry of Health’s (MOH) recommendation on sugar intake suggests “snacks and drinks … are … low in sugar especially added sugar ” and to “limit drinks such as fruit juice, cordial, fruit drink, fizzy drinks (including diet drinks), sports drinks and sports water” [5].

The American Heart Association (AHA) has a more cut and dry nutrition recommendation of fewer than six teaspoons of added sugar per day for children 2-18 years.

Since 1989, World Health Organisation (WHO) has strongly recommended1 children reduce their dietary intake of free sugars to less than 10% of total energy intake (<10% EI) and in 2015 suggested a further reduction of free sugars to below 5% of total energy intake (<5% EI) [8]. This is a conditional recommendation2 and is based on very low-quality evidence where a dose-response between reduced free sugar intakes of <5% EI and reduced dental caries was observed. No evidence of harm has been identified with reducing free sugars to <5% EI [8].

The strong WHO recommendation to restrict free sugar intake to <10% EI is based on moderate quality evidence3 being [8]

  • A meta-analysis of five randomised controlled trials with interventions to encourage children to reduce their sugar intake in food and beverages. The quality of the evidence was moderate but without effect in four of the five studies i.e. no changes in weight loss, this was likely to be due to low compliance by the study participants (children) willing to follow the dietary advice intervention [9].
  • A meta-analysis of prospective cohort studies did find associations with one or more servings of sugar-sweetened beverages per day and overweight or obese children [8], [9].
  • An effect of reducing or increasing sugar is dose dependent with regards to body weight – more sugar, higher BMI [8].
  • The evidence for the effect of increasing free sugar intake on body weight in children is of low quality [8].
  • Observational studies have found moderate quality evidence for a positive association between dental caries and sugar intake [8], [9], regardless of exposure to fluoride [8].

This is where it all becomes tricky, what exactly is ‘sugar’ – total, free or added? MOH describe sugar as monosaccharides and disaccharides. WHO talk about ‘free sugar’ and AHA refer to added sugar. Sometimes when comparing sugar it is not quite ‘apples’ to ‘apples’ but more a generalisation and you need a feel for the situation
FP Sugars and the Nutritional Information Panel

And do we meet the guidelines?

The University of Sydney recently evaluated the free sugar intake of the Australian population (10) and the University of Otago has done the same for New Zealand adults (11).  The graph, below, shows the average free sugar intake as a % of energy is higher than the WHO recommendation for all age groups except 51-70 year olds.

FP003 ANZ free sugar intake
The average “free” sugar intake for the Australian and New Zealand populations is primarily higher than the recommended intake (<10% EI) from World Health Organisation

Australian children’s (2-14 years) mean intake of free sugars was between 11.5 and 13.8 of total EI.  New Zealand does not have a free sugar intake calculated for NZ children.  My rough calculation of children’s free sugar intake, based on the 2002 Nutrition Survey for Children, was an average of 12% for boys and girls aged 2-14 years4 – higher than the recommendation but a formal study is required as my data was old and limiting.  Perhaps it is time for another Children’s Survey.

So now what?

Awareness of what is in our foods is key – excess sugar is associated with excess body fat, NZ children are consuming too much sugar, obese children become obese adults and obesity is associated with non-communicable diseases.

Nutrition research is in its infancy and WHO feels more research is required to evaluate different behavioural-change approaches to help promote the reduction of free sugars in children thus creating higher compliance rates in randomised controlled trials [8].

I cannot wait that long and feel that we are all in this together and need to take personal responsibility with regards to our (and our children’s) sugar consumption. Is it necessary to regularly buy sweet treats for our children – is this an act of love?

References

1. Lal A, Moodie M, Ashton T, Siahpush M, Swinburn B. Health care and lost productivity costs of overweight and obesity in New Zealand. Australian and New Zealand Journal of Public Health 2012;36(6):550-6. doi: 10.1111/j.1753-6405.2012.00931.x.

2. Ministry of Health. Health loss in New Zealand 1990-2013: A report for the New Zealand Burden of Diseases, Injuries and Risk Factor Study. Wellington: Ministry of Health, 2016.

3. Swinburn BA, Sacks G, Hall KD, et al. The global obesity pandemic: shaped by global drivers and local environments. The Lancet 2011;378(9793):804-14. doi: https://doi.org/10.1016/S0140-6736(11)60813-1.

4. Ministry of Health. Children and young people living well and staying well: New Zealand Childhood Obesity Programme Baseline Report 2016/2017. Wellington: Ministry of Health, 2017.

05. Ministry of Health. Food and nutrition guidelines for healthy children and young people (aged 2-18 years): A background paper. Partial revision February 2015. Wellington, New Zealand: Ministry of Health 2015.

6. Ministry of Health. Understanding excess body weight: New Zealand Health Survey. Wellington: Ministry of Health, 2015.

7. Ministry of Health. NZ Food NZ Children: Key results of the 2002 National Children’s Nutrition Survey. Wellington: Ministry of Health, 2003.

8. World Health Organisation. Guideline: Sugars intake for adults and children. 2015.

9. Te Morenga L, Mallard S, Mann J. Dietary sugars and body weight: systematic review and meta-analyses of randomised controlled trials and cohort studies. BMJ (Clinical research ed) 2012;346:e7492-e. doi: 10.1136/bmj.e7492.

10. Lei, L., Rangan, A., Flood, V., & Louie, J. (2016). Dietary intake and food sources of added sugar in the Australian population. British Journal of Nutrition, 115, 868-877. doi: 10.1017/S0007114515005255.

11. Kibblewhite, R., Nettleton, A., McLean, R., Haszard, J., Fleming, E., Kruimer, D., & Te Morenga, L. (2017). Estimating Free and Added Sugar Intakes in New Zealand. Nutrients, 9(12), 1292.

Footnotes

1. A strong recommendation from WHO suggests the desirable outcome from the recommendation outweigh any undesirable outcome
2. There is less certainty between the benefits and harms or disadvantages of implementing this recommendation still requires debate
3. Moderate quality of evidence = moderately confident that the true effect lies close to the estimate effect ut there is a possibility that it could be substantially different. Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate
4.Based on the median daily (total) sugar intake for NZ children (127 g for boys and 115 g for girls), 51% and 50% was from beverages, sugar and sweets, biscuits, cakes, desserts and cereals, which equates to 65 and 58 grams and my estimate of free sugar intake. Using a median energy intake of 9.1 MJ for boys and 7.8 MJ for girls from the same study, my estimated ‘free sugar’ consumption for both NZ boys and girls is 12% of energy.
Sugar produces 16.7 kJ per gram .. 65 g of sugar produces 1085.5 kJ (65 * 16.7) of energy .. this equates to 12% of total energy intake (1085.5/9100).

Does a healthy lifestyle include nuts or are nuts healthy?

A University of Otago study identifies the profile of nut consumers and the associations between nut consumption and chronic disease.

A recent paper published by University of Otago, titled  “Associations between Nut Consumption and Health vary between Omnivores, Vegetarians and Vegans[1], had ‘tweeted posts’ sending a confusing message.  Continue reading “Does a healthy lifestyle include nuts or are nuts healthy?”