Macadamia Health Benefits

The Mediterranean Diet Pyramid

Macadamia nuts (raw kernel): Per 100g serve

• Energy: 3080kJ
• Moisture: 1.2g
• Protein: 9.2g
• Fat (total oils): 74.0g
• Monounsaturates: 60.0g
• Polyunsaturates: 4.0g
• Saturated: 10.0g
• ASH (minerals): 1.3g
• Carbohydrates (total): 7.9g
• Sugars: 4.6g
• Dietary Fibre: 6.4g
• Cholesterol: Nil
• Calcium: 64mg
• Potassium: 410mg
• Sodium: 2mg

Source: AGAL

Above relates to edible portion only

Variety and seasonal conditions may cause minor variations in above values.

Australian Macadamia Oil: Per 100g

• Energy: 3436Kj
• Protein: Trace
• Fat (Natural oils): 100g
• Monounsaturates: 80.5g
• Polyunsaturates: 2.5g
• Saturated: 16.6g
• Carbohydrates (total): Nil
• Sugars: Nil
• Cholesterol: Nil
• Sodium: Trace
• Potassium: Nil

Nutrition Facts and Health Benefits of Macadamia Nuts

Macadamias are considered the world’s finest nut and are the only native Australian plant to become an international food. Their delicate flavour, versatility and crunchy texture make them a delight to consume. Also they contain a range of nutritious and health promoting constituents and form an important part of a healthy diet. A balanced diet containing macadamias promotes good health, longevity and a reduction in degenerative diseases.

The image of macadamia and other tree nuts is changing as research, dietary trials and population studies demonstrate their importance as part of a healthy diet. This increasing knowledge and understanding of health benefits is likely to alter public perception so that macadamias may be selected primarily for their nutritive and health value apart from their great flavour and texture.

Research from other tree nuts with similar composition is often applicable to macadamias and other tree nuts have been proven to have significant health benefits. The Mediterranean Health Pyramid or diet recommends tree nuts be eaten daily. The good news is you don’t have to think of breaking your diet by eating macadamias. There is increasing evidence that they have a positive effect on many aspects of our health and they are full of important nutrients including monounsaturated fats, proteins, dietary fibre, minerals, vitamins, and phytochemicals.

The Australian Macadamia Society, nutritionists, medical researchers and food scientists are undertaking ongoing research into nutritional and health benefits of macadamias which means available information is being updated. Current projects being undertaken are a full biochemical analysis and nutritional profiling of macadamias and in the USA a phytochemical analysis is close to completion. The Australian research is being funded by macadamia growers together with a subsidy from the Australian Government.

Composition

As macadamias are a natural product their composition may vary due to the growing district, variety, cultural procedures and growing season. The composition of both raw, dried and roasted Australian macadamias typically contain the following:

• Natural oils: 74%
• Moisture: 1.2%
• Protein: 9.2%
• Dietary fibre: 6.4%
• Carbohydrates: 7.9%
• Mineral matter: 1.3% including Potassium, Phosphorus, Magnesium, Calcium, Selenium, Zinc, Copper and Iron
• Vitamins: Vit. B1, B2, B5, B6, Vit. E, plus niacin and folate
• Phytochemicals: Antioxidants including polyphenols, amino acids, selenium and flavanols plus plant sterols
• Energy value: 3080 kilojoules per 100g [747 calories]
• Macadamias contain no cholesterol as they are a natural plant food.
• Macadamias are not genetically modified and only contain natural genes.
• Macadamias do not contain any trans fatty acids.

It is most probable that the health benefits of macadamias are increased by a synergistic effect between its constituents and enhanced by complex biochemical interrelationships working together in our bodies. Whilst we cannot yet demonstrate the combined effect and benefits of the complex natural constituents, the presence of high levels of monounsaturated oils, a wide range of phytochemicals, vitamins, minerals and dietary fibre should provide benefits beyond those of the individual components. Macadamias can be described as a functional food as the physiologically active constituents present provide health benefits greater than the base nutrients.

The University of Newcastle has recently completed a project on health benefit of macadamias which was a dietary study. It demonstrated a significant improvement in markers for oxidative stress, clotting tendency and inflammation. Persons with elevated cholesterol levels showed an improvement in cholesterol and blood fats. These people also had a slight weight reduction despite an increase in the total amount of fat consumed.

Separate dietary trials in Australia and Hawaii with macadamias have demonstrated a significant reduction in total blood serum cholesterol, a reduction in total blood triglycerides, reduction of the undesirable low density cholesterol and with little or no effect on the desirable high density cholesterol. These are all recognized indicators for the risk of heart disease. A range of tree nuts including macadamias have been shown to lower blood pressure in hypertensive people.

A series of dietary trials on tree nuts throughout the world coupled with research has demonstrated a risk reduction with heart disease, certain cancers and related disease, hypertension as well as promote well being and food satisfaction.

Oil

A typical composition is:
Saturated fatty acids: 12.5%
Monounsaturated fatty acids: 83.5%
Polyunsaturated fatty acids 4.0%

The oil in macadamias is largely monounsaturated which is often described as the “good oil”. Macadamias contain a higher percentage of monounsaturated oils than any other natural product. Macadamia oil is similar to olive oil in its composition and use. Macadamias are low in damaging saturated fats, low in polyunsaturated fats which oxidize readily and are high in monounsaturated fats. Consuming less fat has been a health message but the type of fat is much more important than total fats. Diets containing moderate fat levels promote satiety and have been shown to be sustainable and enjoyable in the long term. Low fat diets have often been shown to be unsatisfying and difficult to maintain. The desirable Mediterranean Health Pyramid diet has 40% of the food energy coming from fat.

Protein

Macadamias contain significant levels of protein which are an essential component of our diet and in our bodies form muscle and connective tissues, hair and nails, are part of our blood and act positively on many aspects of our health.

The protein in macadamias comprise essential and non essential amino acids. Macadamias contain all the essential amino acids, with most present at optimum levels.

Dietary fibre

Dietary fibre is becoming better understood and thus more important in human health. Dietary fibre was once called roughage and comprises complex carbohydrates including many types of both soluble and insoluble fibre. In macadamias the walls from millions of cells in each kernel essentially comprise the dietary fibre. Complex carbohydrates include hemicelluloses, lignans, cellulose and gums. Dietary fibre are those carbohydrates resistant to acid and enzymatic attack in the stomach and first intestine and thus pass through into the digestive tract where they promote desirable intestinal bacteria and beneficial physiological processes.

Dietary fibre promotes satiety, provides roughage, slows digestion and reduces hunger and may assist in reducing constipation and diverticular diseases, reduce hemorrhoids, bowel cancers and irritable bowel syndrome. It functions in conjunction with other constituents of macadamias and plays a role in reducing the risk of cardiovascular diseases, cancers and diabetes.

Macadamia contains approximately 7% dietary fibre and current research is attempting to better understand the components that comprise this.
Carbohydrates

Most of the simple carbohydrates are present as sucrose, fructose, glucose and maltose plus some starch based carbohydrates. Carbohydrate supplies energy to the body.

Mineral Matter

Macadamias contain a wide range of minerals which contribute to our bodies requirements.
Typical levels are:

• Potassium: 410mg per 100g
• Phosphorus: 200mg per 100g
• Magnesium: 120mg per 100g
• Calcium: 64mg per 100g

Smaller amounts of sodium, selenium, iron, manganese, copper and zinc are present.

Potassium is associated with fluid balance and volume. Other functions are in carbohydrate metabolism, protein synthesis, muscle contraction and nerve impulses.

Phosphorus plays a variety of roles including mineralisation of bones and teeth, energy metabolism, absorption and transport of nutrients and as a component of DNA and RNA.

Magnesium has many functions in the body. It interacts with other elements and plays a role in bone metabolism, glucose and fatty acid metabolism and in protein synthesis. Magnesium is important in nervous activity and muscle contraction.

Calcium is the major component in bone, bone formation and teeth. It plays an important part in many other body processes.

Selenium is becoming increasingly more relevant due to being part of a key enzyme in a major antioxidant and its joint functions with Vitamin E. It has been recognized as having an anti cancer effect and may behave as an anti-inflammatory agent and assist in the control of rheumatoid arthritis.

Vitamins

Macadamias contain small but significant amounts of a range of vitamins.

• Typical levels are:
• Vitamin E: 1.5 mg per 100g
• Vitamin B1 [thiamin]: 0.7 mg per100g
• Vitamin B5 [pantothenic acid]: 1 mg pr 100g
• Vitamin B6: 0.4 mg per 100g
• Vitamin B2 [riboflavin]: 0.1 mg per 100g
• Niacin: 2 mg per 100g
• Folate [folic acid]: 10 mcg [microgram] per 100g

Vitamin E content varies largely due to the freshness of the kernel and is present as derivatives of Vitamin E. It acts as an important antioxidant, protects cell walls and red blood cells.

Vitamin B1 is a co enzyme important in releasing energy from carbohydrates.

Vitamin B5 promotes a healthy nervous system and releases energy.

Vitamin B6 is involved with protein metabolism and is more important in pregnancy, the elderly and with heavy drinkers.

Vitamin B2 is important in growth of new tissues, healthy skin and eyes.

Niacin converts food into energy and promotes healthy skin.

Folate assists in forming red blood cells and in utilization of protein. It is regarded as essential in pregnancy in minimizing birth defects.

Phytochemicals

Phytochemicals are an important group of natural chemicals of plant origin that are becoming increasingly important in our health. They are trace constituents that are not nutrients as such but play an important role in maintaining health. Their chemistry is complex and interrelated. There are many thousands of phytochemicals which is a new form of science where our knowledge will rapidly increase. They can be compared with the discovery of vitamins nearly 100 years ago.

Research is currently being undertaken to identify and better understand their role in macadamias and a number of different types have been found. A wide range has been found in other tree nuts and it is reasonable to expect that at least some of these will be present in macadamias.

Phytochemicals exhibit physiological effects and may modify risk factors with a number of diseases.

The main class present in macadamias are antioxidants. Antioxidants are scavengers of free radicals and play a significant role in protecting living systems from oxidation and damage. They may minimize degenerative diseases such as cancer, cardiovascular disease and others.
Macadamias contain a range of antioxidants including Vitamin E as tocopherols and tocotrienol, epicatechin [which is the principle antioxidant in tea], the amino acids methionine and cysteine and selenium. Other antioxidants have been detected in lesser amounts.
Macadamias also contain phytosterols [plant sterols] which are believed to lower total serum cholesterol and the undesirable low density cholesterol. Macadamias contain a range of sterols constituents of which sitosterol is the most significant.

Are macadamias fattening?

Some people fear that nuts may be fattening because of their oil content. They make our food tasty and promote satiety. It has been demonstrated that low fat diets are unsatisfying and difficult to maintain. The substitution of nuts for other foods in dietary trials did not result in any weight gain.

A dietary trial at Harvard University compared a low fat, low calorie diet with a low calorie diet containing ample fat from nuts and olive oil. Over 12 months both groups lost an average of 4.5 kgs with the diet containing nuts more successful in keeping weight off after a further 6 months and the participants showed no change in blood pressure. The summary concluded that healthy fats can be part of a weight loss program as long as total calories are controlled. When adding fat calories to a reducing diet it is essential to choose foods such as nuts that are rich in monounsaturated fats, vitamins, minerals, dietary fibre and phytochemicals as well as flavour.

Disclaimer: This report is prepared in good faith from a range of sound independent sources. No person should act on any aspect without first obtaining specific, independent professional advice.

Summary of health benefits:

• Research* has shown that macadamias can help lower blood cholesterol levels
• Research* has shown that macadamias may reduce the incidence of heart disease
• High in fibre
• Very high proportion of monounsaturated fat
• No cholesterol
• Contain vitamins, minerals and protein essential in a healthy diet
• AND they taste great, too!

*Research in support of the health benefits of macadamias

Comparison of a high mono-unsaturated fatty acid diet (enriched with macadamia nuts) and a high carbohydrate diet on blood lipids
D. Colquhoun, D. Moores, J. Humphries, S. Somerset
Wesley Hospital, Brisbane, Australia
May 1992

A diet rich in monounsaturates is an alternative cholesterol lowering diet to a low total fat diet. Most studies have used olive oil as a rich source of monounsaturates. Olive oil is composed mainly of oleic acid (C18:1). The native Australian macadamia nut, arguably the world's most delicious nut, is a fatty nut rich in monounsaturates (80% of energy). This nut has an unusually high content of the monounsaturate palmitoleic acid (C16:1) which contributes 20% of energy.

A randomised trial was conducted comparing a macadamia enriched diet (MD) (40% fat, 20% macadamia) and a high complex carbohydrate diet (CHD) (20% fat) on blood lipid levels. Fourteen subjects aged between 25 and 59 years, with initial blood cholesterol between 4.0 and 8.0 mmol/L were allocated either the MD followed by the high CHD or vice versa. Each dietary phase lasted four weeks, with blood lipids measured prior to study entry and repeated at end of each study phase. Results are set out in table:

* Significantly different from Pre-Entry (p<0.01)

The results demonstrate that a high monounsaturate diet, rich in macadamia nuts, is similar to a low fat, high complex carbohydrate diet in lowering blood cholesterol. It also lowers triglyceride levels.

Health benefits of macadamia nuts
A/Professor Manohar Garg et al
Discipline of Nutrition & Dietetics
Faculty of Medicine & Health Sciences
The University of Newcastle
September 2001

This study has sought to examine the potential health benefits of the regular consumption of macadamia nuts. We have focused on four key aspects of human health:

• Oxidative Stress
• Inflammation
• Cholesterol and blood lipids
• Clotting tendency

The study involved the recruitment of healthy male volunteers initially, followed by a cohort of male volunteers with elevated cholesterol levels. Both groups were asked to record their baseline diet, and to provide a blood sample to determine baseline levels of markers for the factors listed above. The volunteers were then required to consume macadamia nuts on a daily basis for four weeks, and to provide additional dietary information and blood samples at the end of this period.

We found a significant improvement in markers of oxidative stress, clotting tendency and inflammation in both groups. In addition, a significant improvement in cholesterol and blood lipids was observed in the group of volunteers with elevated cholesterol levels. A small but significant reduction in weight was also observed in this group of volunteers, despite an increase in the total amount of fat consumed.

These data suggest that macadamia nuts may be a useful adjunct in the dietary management of elevated cholesterol levels and other risk factors of coronary artery disease.

The effect of macadamia nuts rich diet on life style related diseases
Professor Katsumi Ikeda and Professor Yukio Yamori
Frontier Health Science, Mukogawa Women's University, Hyogo, Japan
December 2004

The aim of this study is to observe any health beneficial effect of a macadamia nut rich diet in young women.
After health examination of young female students aged 18-23 years, they were randomised into three groups, 20 in each, and were given three kinds of rolls topped with macadamia nuts, coconut or butter for 3 weeks. Physical and metabolic parameters were measured before and after the intervention.

Body weight (BW) and body mass index (BMI) were reduced significantly in the group fed macadamia nuts from the initial levels (BW: 49.4 ± 1.2 ? 49. 0± 1.1kg, BMI: 19.9 ± 0.4 ? 19.7 ± 0.4 kg/m2, p<0.05). In addition, serum total cholesterol (TC) and LDL cholesterol (LDL-C) concentrations were decreased from their initial levels significantly in the group fed macadamia (TC: 180 ± 6 ? 169 ± 5 mg/dl, LDL-C: 97 ± 5 ? 90 ± 4 mg/dl, p<0.05), and in that fed on coconuts (TC: 180 ± 5 ? 169 ± 5 mg/dl, LDL-C: 103 ± 4 ? 94 ± 3 mg/dl, p<0.05). In these two groups despite the reduction of TC, the ratio of LDL/HDL atherogenic index (AI) remained the same within 3 weeks.

This study indicated that macadamia nuts reduced body weight and BMI, and Total Cholesterol in young Japanese women without any risk factors, suggestive of the health benefit of macadamia nuts for life style related disease prevention, if used continuously.

The above research projects were funded by Horticulture Australia Ltd with the financial support of the Macadamia industry.

Source: Australian Macadamia Society