Lupin,
is a legume grain, and has been eaten in many parts of the world for centuries.
It is quite unique in its macronutrient composition, consisting of
approximately 45% protein by weight and 30% dietary fibre, with negligible
available carbohydrate. It can be eaten as a bean, or ground down into a flour,
which can be substituted for wheat flour in baked foods such as breads to
increase protein and fibre, and reduce refined carbohydrate content. Being a
legume, it is also naturally gluten free.
Lupins
have been grown in Australia for many years as part of crop rotation cycles
with wheat, to put nitrogen back into the soil naturally, so lupins are a
highly sustainable crop. For this reason Australia currently produces around
80% of the world’s lupin crop.
Scientists
have only recently begun to explore the potential health benefits of lupins for
human health. An acute study
incorporating 40% Lupin flour into bread (compared to white bread) demonstrated
that people felt fuller for longer and ate less at the next meal (Lee et al.
2006), suggesting regular consumption may lead to weight loss.
Both
animal and human studies have also shown the significant impact of lupin on
blood pressure. One study showed that a diet incorporating lupin flour-enriched
bread compared to a white bread control led to significant differences in
systolic blood pressure, diastolic blood pressure, and pulse pressure over the
16-week trial. Observed differences were 3.0, 0.6, and 3.5 mmHg, respectively
(Lee et al 2009).
Another
12-month randomized controlled trial also explored blood pressure and observed
that relative to control, the mean 24-h systolic and diastolic blood pressure
in the lupin group was significantly lower (Belski et al. 2011). Given that just
a 2-mmHg reduction in systolic blood pressure would translate to a 10% lower
stroke mortality in middle-aged adults (Lewington et al., 2002), the notion of simply
swapping the toast you eat in the morning to improve heart health is a tempting
one.
Lupin
grains have also reportedly been referred to as an antidiabetic product in
traditional medicine (Terruzzi et al. 2011), and researchers have also observed
benefits for blood glucose and insulin levels.
Adding lupin flour to bread has been shown to reduce its GI (Hall et al.
2005). Lee et al. (2006 and 2009) have previously shown that lupin-enriched
foods can acutely reduce postprandial glycemia and insulinemia. Belski et al. (2011) found that a lupin
flour-enriched diet significantly lowered fasting insulin concentrations by 16%
and 21%, and HOMA scores by 30% and 33% at 4 and 12 months, respectively. Dove
et al. (2011) found that adding lupin to a carbohydrate-rich beverage reduces
glycemia acutely in Type 2 diabetic individuals.
These results are exciting but more
research is needed in this area. The food industry and manufacturers are
finally starting to take notice, with a number of commercial products currently
available and more being developed. This
is an exciting space to watch, and an excellent example of using sustainable
legumes that Australia has in abundance in improving the health of Australians!
References:
1. Belski, R, et al. "Effects
of lupin-enriched foods on body composition and cardiovascular disease risk
factors: a 12-month randomized controlled weight loss trial." International
journal of obesity 35.6 (2011): 810-819.
2. Dove, E et al. "Lupin and
soya reduce glycaemia acutely in type 2 diabetes." British Journal
of Nutrition 106.07 (2011): 1045-1051.
3. Hall, Ramon S., Sarah J. Thomas,
and Stuart K. Johns. "Australian sweet lupin flour addition reduces the
glycaemic index of a white bread breakfast without affecting palatability in
healthy human volunteers." Asia Pacific journal of clinical
nutrition 14.1 (2005): 91-97.
4. Lee, Ya P., et al.
"Lupin-enriched bread increases satiety and reduces energy intake
acutely." The American journal of clinical nutrition 84.5
(2006): 975-980.
5. Lee, Ya P., et al. "Effects
of lupin kernel flour–enriched bread on blood pressure: a controlled
intervention study." The American journal of clinical nutrition 89.3
(2009): 766-772.
6. Lewington S, Clarke R, Qizilbash
N, et al. Age-specific relevance of usual blood pressure to vascular mortality:
a meta-analysis of individual data for one million adults in 61 prospective
studies. Lancet 2002;360:1903–13.
7. Terruzzi, I., et al.
"Insulin-mimetic action of conglutin-γ, a lupin seed protein, in mouse myoblasts." Nutrition,
Metabolism and Cardiovascular Diseases 21.3 (2011): 197-205.
