Legumes are relatively inexpensive and nutrient-dense sources of plant protein. Dried peas, beans, lentils and chickpeas are the most common crop varieties. Half a cup of cooked legumes provides 6-8 grams of protein and approximately 5-8 grams of fibre, as a mix of soluble and insoluble fibres. Each one has different health benefits.
Legumes provide B-vitamins and essential minerals such as iron, zinc and calcium. They have a low-glycaemic index, which means they do not cause spikes in blood sugar levels and insulin, and they are rich in dietary fibre and phytochemicals.
Phytochemicals present in legumes
Legumes contain compounds considered ‘anti-nutrients’ because they can block and reduce absorption of some minerals in our body. But these compounds can also provide beneficial effects for human health. These phytochemicals are:
- Enzyme inhibitors – these compounds reduce the digestion of protein. But proper soaking and cooking deactivate them and improve digestion.
- Lectins – can reduce absorption of minerals such as iron, calcium and zinc. Lectins are also deactivated by cooking, sprouting and fermentation.
- Phytic acid – phytates or phytic acids serve as the principal storage form of phosphorus in plants. They can bind and interfere with absorption of proteins, starches and minerals. Sprouting and fermentation help to improve digestibility.
Soaking and cooking reduce the anti-nutrient activity of these compounds. Adding or consuming foods rich in beta-carotene and vitamin C in the same meal also reduce anti-nutrient effects.
What are the benefits of these phytochemicals?
Lectins
Cancer – lectins have inhibitory and beneficial effects in certain types of cancer such as melanoma and colon cancers.
HIV – Lectins from kidney beans help to inhibit HIV virus replication.
Phytic acid – has many healthy benefits documented to date:
Cancer – phytates help to protect and fight cancer.
Cardiovascular disease – may help to lower cholesterol levels and decrease risk of heart disease.
Insulin resistance and Diabetes – inositol, a molecule released from phytic acids during digestion help to improve insulin utilization and regulation of blood glucose levels.
Other important phytochemicals present in legumes have many health benefits:
- Phytosterols – help to lower cholesterol.
- Polyphenols – these compounds form the pigments and give colours to legumes. Hence, the darker crop varieties have the highest antioxidant levels. Pressure cooking legumes increase their antioxidant content.
- Phytoestrogens – legumes contain phytoestrogens such as isoflavones present in soy beans and chickpeas. Phytoestrogens are molecules derived from plants that are able to mimic and modulate the effects of the hormone oestrogen produced in our bodies. Isoflavones help to protect bones from osteoporosis, prevent against cardiovascular disease and cancer, and treat menopause symptoms such as hot flushes.
Legumes can be used in so many wonderful dishes: stews, dahls, soups, chilli con carne, salads, dips, breads. Legumes contain indigestible fibres which feed our gut flora. One issue some people may experience when consuming legumes is increased flatulence. If you are not used to eating legumes regularly, start with small amounts to allow your gut flora to adjust to the increase in fibre and avoid discomfort. Vinegar such as apple cider vinegar can be added to the soaking water, as the acid helps to soften and break down some of these indigestible compounds and reduce flatulence. Furthermore, addition of carminative herbs such as cumin, ginger, fennel, and asafoetida stimulate appetite and improve digestion. So, you can enjoy more of the benefits of this wholesome food.
References:
Campos-vega, R, Loarca-Pina, G & Oomah, D 2010, ‘Minor components of pulses and their potential impact on human health’, Food Research International, vol. 43, pp. 461–482.
Schlemmer, U, Frølich, W, Prieto, R, & Grases, F 2009, ‘Phytate in foods and significance for humans: food sources, intake, processing, bioavailability, protective role and analysis’, Molecular Nutrition & Food Research, vol. 53, no. 2, pp. S330-S375.
