Human milk provides infant with the required nutrients for growth and development. The aim of preliminary study was to determine macro- and micronutrients content in mature human milk among lactating women residing in Latvia and dietary habits affecting it. The study was carried out from November 2016 to February 2017. In total, 24 pooled diurnal milk samples were collected from mothers whose infants had reached the age of at least two months. Personal information of each participant was recorded, including mother’s age, weight and height parameters, sex and age of an infant, parity, breastfeeding pattern, milk expression method used for sampling. Eating habits were obtained using Monthly Food Frequency Questionnaire. Analysed elements were determined using inductively coupled plasma mass spectrometry (ICP‑MS Agilent 7700x, Japan). Concentrations ranged from 227.52 to 398.34 mg LE-1 for calcium, 58.56 – 256.38 mg LE-1 for sodium, 445.33 – 736.71 mg LE-1 for potassium, 25.73 – 49.52 mg LE-1 for magnesium, till 3.17 mg LE-1 for iron, 0.28 – 2.77 mg LE-1 for zinc, 0.06 – 0.43 mg LE-1 for copper, 2.00 – 44.00 µg LE-1 for manganese, 1.00 –10.00 µg LE-1 for chrome which is comparable to data obtained from other studies although chrome and manganese concentration was even higher than observed in literature. Cobalt and selenium content was below detection limit. Zinc content in human milk negatively correlated with baby’s age (p is less than 0.05). The content of majority of essential minerals in human milk was affected by mother’s dietary habits; however, more samples need to be analysed for representative conclusions.

The mean content of minerals in grains varies significantly among different parts of the world as it depends on the type of grain growing conditions and fertilizer application. In this study, the content of minerals in the wheat, oat and barley grains of the crop of the year 2006 from different regions of Latvia were investigated. The grain samples were analysed for K, Mg, Ca, Na, Cu, Mn, Fe, and Zn using Atomic Absorbtion Spectrometer, and for P using spectrophotometer. Phosphorus content in different types of grains varied from 3.10 to 5.65 g kgE-1, potassium - from 4.37 to 6.10 g kgE-1, calcium - from 0.40 to 1.40 g kgE-1, magnesium - from 1.20 to 1.68 g kgE-1, manganese – from 14.50 to 55.54 g kgE-1, copper - from 3.35 to 6.01 g kgE-1, zinc - from 18.72 to 31.84 g kgE-1, iron - from 42.39 to 120.40 g kgE-1, and sodium - from 32.34 to 55.52 g kgE-1. The greatest difference was found between the content of manganese and iron in barley, wheat and oat grains, but small difference was between the mean content of P, K, Zn, Cu, Mg, and Na.

The experiment was carried out in 1990, 1991, 1993 in the Rumokai Research station of the Lithuanian Institute of Agriculture. The following nitrogen norms were analysed: 0(0+0), 45(0+45), 45(45+0), 90(45+45), 90(90+0), 135(90+45), 135(135+0), 180(135+45), 180(180+0), 225(180+45). Sugar production is negatively affected by soluble non-sugar substances (soluble potassium and sodium salts, amines) that prevent crystallization of sugar. Norms of nitrogen fertilisers increased the amount of: potassium by 8.9-38.2%, sodium - 11.0-54.4%, alpha-amine N - 43.0-163.5 %, while additional application of nitrogen -45 kg ha*[-1) - resulted in the increase of: 1.0 - 7.9% potasium, 1.0-8.0 % sodium, 18.2 - 44.9 % alpha-amine N. Strong positive corelation (eta=0.99) has been established between the norms of nitrogen fertilisers and soluble non-sugar substances. Potassium, sodium and alpha-amine N negatively influence the sugar content roots (eta=-0.59). Among the 14 analysed varieties, the amount of low soluble non-sugar substances was significant in the roots of Kristall, Accord and Extra varieties. The highest yield of white sugar has been found in the varieties of Freja, Anna, Accord, Extra (7.3-7.7 t ha*[-1)).